Author Topic: .223/5.56 CALIBER GUIDE: RECOMMENDED READ  (Read 12247 times)

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Offline White Israelite

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.223/5.56 CALIBER GUIDE: RECOMMENDED READ
« on: December 23, 2007, 09:53:00 PM »
This is a backup of a guide I have on the .223/5.56 round. Some of the pictures may be broken

Q. What is the history behind the development of the .223/5.56mm round?

Studies of the fighting in WWII determined that most of the infantry fighting took place at distances under 200 yards, and those figures have not changed much in modern conflicts.(1)  This was a revelation at the time and a controversial one, as ever since the development of smokeless powder, the long distance capabilities of military rifles had been stressed.  It was common for rifles designed in the 1890s through the 1940s to have sights adjustable out to 1,000 or even 2,000 yards, and often not having an adjustment below 200 or 300 yards.  Obviously, there was a discrepancy between the design of these rifles and how they were most often used.

Following WWII, the US military decided it needed a select-fire, detachable-magazine rifle.  (The WWII-era M1 Garand had originally been designed with a detachable magazine, but at the time, the military decided they were a liability for a standard, front-line infantry rifle and had the M1 redesigned.)  During this period during the late 40s and early 50s, many nations were experimenting with smaller-caliber rifles that were controllable in full-auto and allowed more rounds to be carried.  The US military insisted on a 30 caliber rifle, though, and merely shortened the existing .30-06 Springfield (7.62x63mm) round to create the 7.62×51mm round, which Winchester released commercially as the .308 Winchester.  The US also forced this round onto the newly-formed NATO, over protests that it was too much cartridge, would require rifles to be too heavy, and wouldn't be controllable on full auto.  The first point is arguable, but the last two were certainly true.  Still, the US military, having determined that the Belgium-designed FN FAL was a better rifle then the domestic M14 (a modified M1 Garand), chose the M14 anyway.  Such is politics.

The M14 program was a political minefield and during the early 1960s, minor US involvement as "advisors" in the southeast Asian country called Vietnam was beginning to escalate.  It didn't take long before the Vietnam expansion, coupled with manufacturing problems with some M14 contractors, resulted in too many soldiers and too few M14s.  The military initially pulled WWII M1 Garands out of storage and pressed them back into service, but these long, heavy rifles were poorly suited to the jungle environment of Vietnam.  During this time, Eugene Stoner of ArmaLite, the armament division of Fairchild Aircraft, had designed a rifle called the ArmaLite Model 10, or AR-10, which was chambered in the current NATO round of 7.62×51mm.  Though the AR-10 was produced too late to enter the M14 competition, ArmaLite hoped to sell the AR-10 to foreign militaries.

Meanwhile, there was a faction of the US Military and the Congress which supported the idea of a lightweight, select-fire rifle firing a mid-power, small-caliber, high-velocity (SCHV) cartridge.  After seeing the ArmaLite AR-10, they discussed their desire for a scaled-down model.  ArmaLite engineers Jim Sullivan and Bob Fremont scaled down the AR-10 to fit the hot varmint cartridge of the day, the .222 Remington.  During some preliminary military testing, it was decided that the .222 Rem wasn't quite powerful enough.  Though the .222 Remington Magnum existed and had the power they were looking for, the severe shoulder angle would have prevented positive feeding in a semi-auto, and so it was decided that the best solution was to lengthen the .222 Rem case.  The result was the 5.56×45mm cartridge, designed by G. A. Gustafson, which Remington released commercially as the .223 Remington.  This cartridge has virtually identical ballistics as the .222 Mag and, over time, the wide availability of .223 guns and ammo has lead to the demise of the .222 and .222 Mag cartridges.

The AR15 was initially adopted by the Air Force, but the need for rifles for soldiers heading to Vietnam gave the "medium-power cartridge" supporters an opening and the AR15 rifle was hastily procured, initially as a one-time purchase.  Continued problems with the M14 program lead to the official adoption of the AR15, which was given the US military designation "M16." 

Fact: The national average engagement range for police 'snipers' has, for the past 20 years, been 78 yards.  The FBI Hostage Rescue Team (HRT) snipers are limited to engagement ranges of 200 yards.  The longest recorded shot taken by a police marksman in the US is 97 yards.  (There are some reports that indicate some longer shots, including one alleged 300 yard shot in 1982 by the U.S. Park Police in response to a bombing threat at the Washington Monument- but these are very rare and not confirmed). The FBI's uniform crime report indicates that the average engagement range in a handgun incident is between 7 and 10 feet.

 

For a more detailed history of the M1 Garand see: The Complete Guide to the M1 Garand and the M1 Carbine, by Bruce N. Canfield.

 

 

 

For a more detailed history of the M16, see: The Black Rifle: M16 Retrospective, by R. Blake Stevens.

For more details about the history of the 5.56x45mm round itself, see A 5.56×45mm "Timeline" by Daniel E. Watters on Dean Spear's The Gun Zone.

Q. What is the difference between 5.56×45mm and .223 Remington ammo?

In the 1950's, the US military adopted the metric system of measurement and uses metric measurements to describe ammo.  However, the US commercial ammo market typically used the English "caliber" measurements when describing ammo.  "Caliber" is a shorthand way of saying "hundredths (or thousandths) of an inch."  For example, a fifty caliber projectile is approximately fifty one-hundredths (.50) of an inch and a 357 caliber projectile is approximately three-hundred and fifty-seven thousandths (.357) of an inch.  Dimensionally, 5.56 and .223 ammo are identical, though military 5.56 ammo is typically loaded to higher pressures and velocities than commercial ammo and may, in guns with extremely tight "match" .223 chambers, be unsafe to fire.

The chambers for .223 and 5.56 weapons are not the same either.  Though the AR15 design provides an extremely strong action, high pressure signs on the brass and primers, extraction failures and cycling problems may be seen when firing hot 5.56 ammo in .223-chambered rifles.  Military M16s and AR15s from Colt, Bushmaster, FN, DPMS, and some others, have the M16-spec chamber and should have no trouble firing hot 5.56 ammunition.

Military M16s have slightly more headspace and have a longer throat area, compared to the SAAMI .223 chamber spec, which was originally designed for bolt-action rifles.  Commercial SAAMI-specification .223 chambers have a much shorter throat or leade and less freebore than the military chamber.  Shooting 5.56 Mil-Spec ammo in a SAAMI-specification chamber can increase pressure dramatically, up to an additional 15,000 psi or more.

The military chamber is often referred to as a "5.56 NATO" chamber, as that is what is usually stamped on military barrels.  Some commercial AR manufacturers use the tighter ".223" (i.e., SAAMI-spec and often labeled ".223" or ".223 Remington") chamber, which provides for increased accuracy but, in self-loading rifles, less cycling reliability, especially with hot-loaded military ammo.  A few AR manufacturers use an in-between chamber spec, such as the Wylde chamber.  Many mis-mark their barrels too, which further complicates things.  You can generally tell what sort of chamber you are dealing with by the markings, if any, on the barrel, but always check with the manufacturer to be sure.

 Typical Colt Mil-Spec-type markings:  C MP 5.56 NATO 1/7

Typical Bushmaster markings: B MP 5.56 NATO 1/9 HBAR

DPMS marks their barrels ".223", though they actually have 5.56 chambers.

Olympic Arms marks their barrels with "556", with some additionally marked "SS" or "SUM."  This marking is used on all barrels, even older barrels that used .223 chambers and current target models that also use .223 chambers.  Non-target barrels made since 2001 should have 5.56 chambers.

Armalite typically doesn't mark their barrels. A2 and A4 models had .223 chambers until mid-2001, and have used 5.56 chambers since.  The (t) models use .223 match chambers.

Rock River Arms uses the Wylde chamber specs on most rifles, and does not mark their barrels.

Most other AR manufacturers' barrels are unmarked, and chamber dimensions are unknown.



Opinion: In general it is a bad idea to attempt to fire 5.56 rounds (e.g., M193, M855) in .223 chambers, particularly with older rifles.


 5.56 v. .223 Remington specification.

Fact: The different manufacturer's chamber types are listed at length and in great detail at: http://communities.msn.com/TheMarylandAR15ShootersSite/ar15brands.msnw

Q. Which should I be looking for in an AR15, a 5.56 NATO or .223 Remington chamber?

 This is really a matter of the role for which you plan to use your AR.  .223 Remington chambers will give you slightly better accuracy, which is important for a match or varmint rifle.  Any loss of feeding and cycling reliability and the restriction against shooting military ammo isn't as important as the accuracy gains for a rifle used in these roles, because for these rifles, accuracy is everything.  People who just want to plink or who plan to shoot military ammo (such as most of the cheap surplus ammo available), and especially those who may use their AR as a weapon, should choose 5.56 chambers.

Opinion: Unless you have a reason to seek out .223 Remington SAAMI spec chambers, 5.56 NATO is probably the best solution.  5.56 NATO chambers still can have outstanding accuracy and give you more flexibility in ammo selection.

Q. What is the circle-cross stamp on some of my ammo?

The circle-cross Å is the NATO symbol.  It indicates that the ammo was loaded in a NATO-approved facility and meets the NATO specifications for that round.  Note that NATO specifications are not the same as US military specifications and that many NATO-approved rounds do not meet  US military specs.  US military specs (such as M193 and M855) have additional requirements, such as minimum velocities, that the NATO specs (like SS-109) don't have.  Fact: There are some exceptions to this rule.  For example, recent Lake City and Winchester M193 is loaded in cases marked with the NATO circle-cross.  This is done simply to save money by having one production run of cases instead of two.  M193 was never adopted by NATO; by the time NATO decided to standardize on 5.56mm, the SS-109/M855 ammo was available, and was adopted as the standard.  M193 is still "Mil-Spec," it just isn't "NATO" spec. 

Q. How can I tell if a round is SAAMI, US military, or 5.56 NATO Mil-Spec?

 Generally if the round is an M193, M855, M196, M856, or SS-109 round it is Mil-Spec.  This FAQ will help you determine the differences between these specs.  Often Mil-Spec rounds sold commercially have similar model numbers, like XM-193.  Another good clue (but not definitive evidence) is the presence of the NATO cross in a circle on the headstamp.  Ammo that has a painted tip (Green for M855) is generally always military ammo.

Generally you don't have to worry unless you're using a .223-chambered rifle, but it's a good idea to check regardless.  Of course, if you have a Mil-Spec chamber, you needn't bother.

NOTE: All bets are off if the ammo in question has been "remanufactured" or "reloaded."  There's no way to know what you've got with reloads, other than the reputation of the reloader.


 NATO stamp on a Lake City 5.56 round from www.ammoman.com.

Q. What is FMJ?  JSP?  JHP?  FMJBT?

 FMJ is "Full Metal Jacket" and is used to describe rounds that are entirely encased (except for the bullet base, typically) in a metal jacket, usually copper alloy called gilding metal.  FMJ rounds are also sometimes referred to as "ball" (meaning "standard") ammunition by the military.  Generally these rounds are designed with little to no expansion in mind.  They are comparatively inexpensive to produce, feed well, give good penetration in most materials.  The jacketed nose prevents bullet expansion and typically leaves the bullet intact after striking flesh (the 5.56 round is a notable exception).

JSP is "Jacketed Soft Point" and is used to describe rounds that are encased in a metal jacket, again, usually gilding metal, but leave the soft lead core exposed at the tip of the bullet.  The soft nose deforms upon striking dense mediums, and these rounds are generally designed to expand rapidly at the nose and mushroom, ensuring that the center of gravity stays in front, and causing the bullet to continue traveling forward through the target.  The larger frontal surface area causes more tissue disruption compared to most non-expanding bullets.

JHP is "Jacketed Hollow Point" and is used to describe rounds that are encased in a metal jacket, gilding metal again, but have a small cavity in the nose along with a round opening in the jacket in the nose.  JHP rounds are also designed for expansion but tend to have faster "mushrooming" effects because the hollow point is filled with high-pressure material when the bullet impacts, often peeling back the jacket and making a "mushroom" shaped projectile.

BT stands for "Boat Tail" and refers to the base of the bullet.  A "Boat Tail" is a sloping end which narrows gently at the base of the bullet, so that the cross-section resembles the shape of a boat's hull.  The boat tail shape reduces drag on a bullet, helping it to retain velocity and resist deflection from crosswinds, but causes the bullet to take longer to "settle" after leaving the barrel compared to a standard "flat-base" bullet.  Boat tail bullets are usually selected for long-range shooting, while the flat-base bullet shape tends to be more accurate at short ranges.  A "HPBT" bullet is a "Hollow Point Boat Tail" bullet.


FMJ Bullet


A JSP Bullet

NO IMAGE
A JHP Bullet


A HPBT bullet

Q. What is "Ballistic Tip" ammo?
 "Ballistic Tip" is actually a trademark of Nosler, who first started making plastic tipped bullets in 1985.

Though originally designed to prevent damage to the bullet nose when feeding (while the nose of a soft tip or hollow point might deform due during feeding to the soft lead content in the nose, a plastic tip bullet will maintain a consistent nose shape) today the primary advantage of a polymer tipped bullets is a high ballistic coefficient. The design also allows the center of gravity to be moved back, increasing in flight stability. This is the same design theory that gives hollow point match bullets better accuracy properties.

In terminal performance, ballistic tips are designed to work like wedges, mashed into the hollow point and inside the jacket on impact, initiating expansion theoretically, quickly and reliably.

Offline White Israelite

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Re: .223/5.56 CALIBER GUIDE: RECOMMENDED READ
« Reply #1 on: December 23, 2007, 10:04:57 PM »
Q. What types of ammo has the US Military used in its M16s and M4s?

The military has used the following ammo types in 5.56mm (excluding blanks and specialty rounds):

M193: 55gr FMJBT Ball, plain tip.

This cartridge is intended for use against personnel and unarmored targets from 5.56×45mm weapons with a 1-in-12-inch (1:12) or faster rifling twist rate (M16 family rifles and other compatible systems).  Its ballistic coefficient is typically .243

M196: 55gr Tracer, short range, red-painted tip.

M855: 62gr FMJBT Ball, green-painted tip.

This cartridge is intended for use against personnel, unarmored and light armored targets from 5.56×45mm weapons with a 1-in-10-inch (1:10) or faster rifling twist (Machine guns: M249 Minimi; Rifles: M16A2 and other compatible systems).  The M855 cartridge is based on the FN-designed SS-109 bullet, and has a gilding metal-jacketed, lead alloy core bullet with a steel penetrator.  The primer and case are waterproof.  It was adopted by NATO in 1980 as the standard small arms ammunition for NATO forces.  Its ballistic coefficient is typically 304.

M856: 61gr Tracer, long range, orange-painted tip.

This cartridge uses the FN-designed L-110, 63.7 grain tracer bullet, which has no steel penetrator. (Note that while FM 23-14 lists this bullet weight for the M856, IMI lists the weight of the L-110 tracer bullet which tops the M856 round as 61.7 grains.  At least one AR15.com member reports 60.8-61.3 weights for a variety of M856 rounds that were pulled).  The long projectile requires a barrel with a 1:8 or faster rifling twist.

M995: 62gr FMJBT AP, black-painted tip.  This FN-designed bullet uses a hardened tungsten-carbide penetrator, and is only available on special-issue SAW belts.

M996: Actually, XM996, as it hasn't been adopted yet.  The tracer compliment to M995.


 Component view of M995 Armor Piercing 5.56mm.

 Fact: The specifications for the various rounds are:

M193: Defined by: Mil-C-9963F
55 grain bullet (q 2 grains) at a muzzle velocity of 3,165 (q 40 fps) from a 20" barrel @ 78 feet from the muzzle.  Accuracy: maximum of a two inch mean radius at 200 yards from ten 10 shot groups (~3 MOA).  "Statistically average" M193 ranges from 1.2 to 1.6 inches mean radius, which is equivalent to 1.8 to 2.4 MOA.  Velocity runs about 3,200 fps due to gas loss through the port.  Accuracy is typically around 2 to 2+ MOA from an M16A1 rifle at ranges of 100 to 300 yards.  M193 ammunition should have 1:12 twist or faster.  M193 is barely stabilized with 1:14 at ambient temperatures and will not stabilize at all when the air temperature drops below freezing.

M855: Defined in MIL-C-63989
NATO specifications for M855 Ball require a 61.7 grain (q 1.5 grains) with a hardened steel penetrator at a velocity of 3,000 fps (q 40 fps) from a 20" barrel @ 78 feet from the muzzle.  Typical velocity 15 feet from the M16A2's muzzle is 3,100 fps.  Accuracy: maximum of approximately four MOA over the 100 to 600 yard range.  Typical accuracy of average lots in an M16A2 is about 2+ MOA.  This round must also penetrate a nominal 10 gauge SAE 1010 or 1020 steel test plate at a range of at least 570 meters (623 yards).  The M193 round will penetrate this same plate reliably at 400 yards and about half the time at 500 yards.  The 5.56mm and 7.62mm NATO rounds will penetrate it reliably out to 700 yards or more.  Because the steel penetrator increases the length and changes the weight distribution of the SS-109 bullet, it is suitable for use only in barrels with a twist of one turn in nine inches or faster.  1:10 twist will barely stabilize this round and not below zero degrees F.

Reloaders: Both M855 and M193 in the US generally use Olin Ball WC844 propellant.  Apparently H335 is roughly equivalent to WC844.

Q. What is SS-109?  Is it the same as M855?

SS-109 is Fabrique Nationale's (FN's) name for their 61.5 grain bullet with the steel penetrator in the nose and what they call rounds loaded with this bullet.  (FN calls M193-type ammo "SS-92.")  The US military's M855 round is loaded with the SS-109 bullet, though the US military has additional specifications that ammo must meet before it can be called M855.  So, while all M855 is loaded with SS-109 bullets, all "SS-109 ammo" will not meet the M855 specs.  For example, the British purposely underloaded some lots of their ammo in an effort to get their L85A1 (SA80) rifles to cycle properly.  The ammo is still loaded with SS-109 bullets and labeled as SS-109, but it is nowhere near the M855 velocity specifications.


Q. What type of ammo is current issue for US Military forces?

All front-line forces are armed with M16A2s and M4s and are issued M855 as standard-issue ammo.  A few remaining Reserve and National Guard units, as well as some Air Force units, still carry M16A1s (you've probably seen them in the airports lately) and are issued M193 Ball (if they are issued any ammo at all) because of the difference in twist of the barrel.

Some special forces units, particularly in Afghanistan and Iraq, are using Mk262 and Mk262 Mod1 ammo.  These are rounds loaded with heavy (up to 77 grain) JHP match bullets, in response to some issues with M855 terminal performance.  This continues a recent trend towards heavier rounds (69 grains and over) for improved terminal ballistic performance.

Q. What about Mk262 or Mk262 Mod1?

Due to the poor performance of M855 ammunition, particularly in short-barreled carbines of 10.5-14.5" in length, Navy SEALs, and eventually other SOCOM units, began experimenting with using loads originally designed for marksmanship units for combat.  It was soon discovered that while these loads were both very accurate and had excellent terminal ballistics even from short barrels, the loads weren't quite ideal for combat.  The target bullets had no cannelure, and the bullets weren't crimped in place, which could allow bullet set-back during feeding and raise chamber pressures to dangerous levels.  Further, most loads were of somewhat mild velocities, as the load was chosen with accuracy, not terminal ballistics, in mind.

Sierra was asked to produce a bullet cannelured version, but they intially refused.

Nosler did not have any problems putting a cannelure on their 77 gr bullet. Black Hills Ammunition was approached to make a slightly modified version of these loads for combat use.  A cannelure was specified, the bullets were to be crimped, and the load was to be up to military chamber pressures, with maximum safe velocity being desired.  The primers were to be crimped and sealed, and of course, overall length had allow for loading in standard magazines.

The Marines (in conjunction with a large Federal LE agency) did extensive testing of this large experimental batch of BH loaded Nosler 77 gr cannelured OTM's in the Fall of 2002. It offered outstanding terminal performance out to the maximum test distance of 300 yards. They then ordered 1.1 million rounds of cannelured 77 gr OTM's via the existing Mk262 SOCOM contract (which did not specify a manufacturer) administered through Crane. The cannelured 77 gr load was designated Mk262 Mod 1, and the orginal Mk262 was re-designated Mk262 Mod 0.



According to one observer: "At this point bureaucracy, nepostism, and capitalism converged. Sierra realized they were about to lose a VERY LARGE contract and suddenly they agreed to make the 77 gr SMK with a cannelure. Crane pushed for Sierra to get the contract over Nosler, although the Nosler offered better terminal performance. On the other hand, in all fairness, the Sierra bullet was slightly more accurate out of government test barrels than the Nosler--both shoot nearly the same out of real rifles, such as the by then type classified Mk12 SPR."

Therefore, while a few hundred-thousand rounds of 77 gr Nosler OTM was manufactured and used primarily for testing, the cannelured 77 gr SMK was used in the the multi-million round contract for the Mk262 Mod 1.

Recently, Sierra agreed to add a minimal crimp to their bullet, and this has since replaced the Nosler bullet in the current versions of Mk262 Mod1.  As of April 2004, Mk 262 Mod1 has seen extensive use in Afghanistan and Iraq, in carbines with barrels as short as 10.5", and has proven to be very effective at ranges that M855 is woefully inadequate from the same weapons.  It is also commonly used in the Army's "Special Purpose Rifles" (SPRs), which  are accurized 18"-barreled rifles used by soldiers with additional combat marksmanship training in a squad sharp-shooter role.

Q. Why did the US Military adopt M855 for the M16?

M855 and M856 are newer rounds developed in the late 1970s by Fabrique Nationale (FN) of Belgium.  FN was developing a new 5.56mm belt-fed machine gun they called the "Minimi" (Mini-Machinegun) for entry into the US military's Squad Automatic Weapon (SAW) program.  The SAW was to augment, and in many cases replace, the 7.62×51mm M60 made by Saco Defense (now part of the General Dynamics Armament Division).  Because there was a lot of resistance to giving up larger, longer-range round of the M60, FN focused on making the SAW perform better at longer ranges than existing 5.56 platforms (i.e., the M16).  They did this primarily by developing new bullets: the SS-109 "ball" round and the L-110 tracer.

The SS-109 bullet uses a "compound" core, with a lead base topped by a steel penetrator, all covered in a gilding-metal (copper alloy) jacket.  The L-110 tracer bullet has a copper-plated steel jacket and like all tracer bullets, is hollowed out at the base and filled with tracing compound.  Both bullets are much longer in length than the earlier 55gr bullets, especially the L-110 tracer, which was designed to trace out to 800m, verses 450m for the older M196 tracer round.  Due to their increased length, these bullets require a faster rifling twist to be properly stabilized.  The military settled on a twist rate of 1:7, which is a compromise between the 1:9 twist ideal for SS-109 bullets and the 1:6 twist ideal for L-110 tracers.

Remember, the goal of these new bullets was improving long range performance.  For example, the SS-109 bullet was proven to have better penetration of the then-current-issue steel helmet at 600m than the M80 "ball" ammo fired by the M60.  The M80 ammo was not able to penetrate both sides of the helmet at that distance; the SS-109 bullet could.  The L-110 tracers provided a visible trace out to 800m, which was seen as the maximum effective range of the SAW.  These improvements in long-range performance satisfied the military and the US ultimately adopted the Minimi as the M249 SAW.  They also adopted the new FN bullets and the US specs for the loaded rounds are called M855 and M856.

About the time the SAW was adopted, the M16 "A2 revision" program was underway and it was decided to adopt the new SAW ammo (and its rifling twist) for the M16A2.  As older M16A1 1:12 twist barrels were not able to stabilize the longer bullets, the new bullets had to be marked (in countries with older 1:12 rifles) in order to make sure that the new ammo wasn't used in the older rifles.  M855 received green painted tips and M856 received orange.  M193 is plain and M196 is red. 

Take a look at:

Fabrique Nationale (FN) http://www.fnmfg.com/

The Minimi from FN--precursor to the SAW. http://www.fnmfg.com/products/m249/M249.htm


The M249 Squad Automatic Weapon (SAW)

Q. So why don't all US military units carry M855?

The original ammo for the M16 was M193, with a 55gr copper-jacketed lead-core bullet.  The rifling twist on the first M16s was 1 turn in 14 inches, or 1:14.  This twist rate was selected simply because it was the twist rate commonly used in the .222 Remington-chambered varmint rifles that the .223 round was based on.  During tests of the M16 in arctic regions, it was found that the slow 1:14 twist wasn't fast enough to stabilize the 55gr bullet in the denser air.  To correct this problem, the twist was tightened to 1:12 and all future M16s and M16A1s came with 1:12 barrels.

The M855 round and particularly the M856 tracer round, are very long bullets and require a faster twist rate in order to be stabilized in air.  Firing M855 from a 1:12-twist rifle would result in an understabilized bullet that would only fly straight for about 90 yards, then veer off as much as 30° in a random direction.  In order to prevent soldiers from accidentally firing M855 in 1:12-twist rifles, M855/SS-109 was given a green-painted bullet tip.  This allows M855/SS-109 to be differentiated from plain-tipped M193.  M16A2s, A3s, A4s, M4s and M4A1s all have a 1:7 twist and can stabilize both M855 and M193. 

 




Fact:  Stabilization is a factor of caliber (bullet diameter), velocity, and bullet length, not bullet weight.

Q. Is all SS-109/M855 ammo marked with green bullet tips?

No.


Countries that previously issued 5.56mm rifles with a 1:12 barrel twist will mark their SS-109/M855 ammo with (usually) green bullet tips, to prevent the ammo from being accidentally fired in the older 1:12 rifles.  Also, countries that regularly supply other countries with older 1:12 rifles usually mark their bullets for the same reason.  Countries that didn't adopt 5.56mm rifles until the NATO SS-109 standard was adopted usually don't mark their ammo with green tips, as they don't have any old 1:12 rifles to be concerned with.  Note that many other countries that now use 5.56 weapons were still using 7.62mm rifles until recently and never used any other ammunition than the SS-109/M855 and L-110/M856, so they don't mark their bullets with green or orange paint unless they intend to sell it to countries who require these markings (the US, Germany, and Belgium, primarily).  They also typically refer to their rounds by the FN bullet name.

Performance of .223 and 5.56 Ammunition.
   

Q. I have my rifle zeroed with M855 ammo.  Will any 62gr ammo shoot the same?

No.


While M855 uses a 62gr bullet, it is a longer bullet due to the steel penetrator in the front of the bullet core.  Steel is less dense than lead, so more volume of steel is needed to end up with the same weight (mass).  There is also a small air cavity in front of the penetrator, unlike a bullet with a solid lead core.  Any non-M855/SS-109 62 grain ammo (such as Wolf and Federal's American Eagle 62gr FMJ offerings) will have a solid lead core, and the resulting bullet will be significantly shorter than an SS-109 bullet.  That means you can expect trajectory and penetration performance to differ as well.

Q. Do M193 and M855 shoot to the same point of impact?

No...


...but within 300 yards, they're generally close enough (for combat use) that rezeroing isn't necessary.  Obviously, you wouldn't want to switch from one to the other for a match without rezeroing.  Consider the graphs below with battle zeros for each round.  (250m zero for M193, 300m zero for M855).


The big differences in bullet path are past 400 meters.

 
A: M16A1 firing both M193 and M855, zeroed for M193.
B: M16A2 firing both M855 and M193, zeroed for M855.

Fact: The Scoop from the Army's   Ammunition Information Notice (61-01) "INTERCHANGEABILITY OF 5.56MM BALL, TRACER AND BLANK AMMUNITION."

Do not zero M16A2, M16A3 rifles or M4 and M4A1 carbines with M193 and then fire M855/M856 as performance will be affected.

Fact: Generally M193 is zeroed out to 250 meters for the flattest trajectory.  Using that "battle zero" the round is never more than 4 inches from the point of aim until almost 300 meters.

By contrast M855 is usually "battle zeroed" to 300 meters.  With this zero the M855 round is never more than 6 inches from the point of aim until 325 meters.

Comparing the bullet paths with these zeros out to 300 meters, we find that M855 is about 5 inches higher than M193 at 300 meters.

Q. OK, what is all this stuff about rifle twists and different ammo?

 Rounds in flight spin for stability because of the rifling on the inside of the barrel.  Depending on how much they spin, they are more or less stable in their flight and therefore more or less accurate.  The earliest AR15s from the early 1960s had a twist rate of 1 complete twist every 14", or 1:14.  This was increased to a twist rate of 1 turn in 12" for the M16, XM16E1, M16A1, and later rifles and carbines.  The current M16A2s and up and the M4 carbines have a much faster twist rate, 1 turn in 7".  The reason for the 1:7 twist is mainly to stabilize the M856 tracer bullet, which is much longer than other bullets.  You will recall from above that the M856 was designed to provide 800 meters of trace out of the SAW.

While the slow 1 in 12" twist is adequate to stabilize the 55 grain M193, it will not stabilize the 62 grain M855.  As a result, the newer M855 ammo will group 1-2 feet at 100 yards, with bullets flying through the air sideways, instead of shooting to about 2" at 100 yards, like military ammo should.

All this has some ramifications for ammunition selection depending on your rifle's rate of twist.

You can also overspin projectiles and cause overstability. This results in the not-so-desirable condition that keeps the nose of the round pointed high, as illustrated below:



 You can also spin them so hard they fly apart.  That's rare, but it happens if you are dealing with very tight twists and very high velocities.  When fired at 3200 fps in a 1-in-7 twist rifle, a round is rotating at over 300,000 rpm when it leaves the muzzle.  Light, thin-jacketed varmint bullets (i.e., 40gr Hornady TNT or Federal Blitz bullets) often can't take that much spin and will pull themselves apart.   

Fact: Generally you want a gyroscopic stability factor (Sg) of 1.3 or greater in a given round, about the low end for normal shooting.  You get this on the larger M855 round with a 1 in 9" twist.  By comparison a 1 in 10" twist will keep that M855 round down to about 1.2- not enough if it starts to get cold.  Really you want stability to be between 1.5 and 2.0- a 1 in 8" twist on a M855 round.  In actuality a 9" twist is a bit better for accuracy as it doesn't spin up non-balanced bullets too fast causing them to wobble in flight.  If you have match rounds, well balanced and tested, you don't really have to worry about overtwisting until you hit 5.0 or so.


The result of unstabilized bullets:
A 1 in 12" FN-FNC firing M855 at 100 yards.
(Note the profiles cut out of the target).

Math and Physics: A spin-stabilized projectile is said to be gyroscopically stable, if, in the presence of a yaw angle, it responds to an external wind force with the general motion of nutation and precession.  In this case the longitudinal axis of the bullet moves into a direction perpendicular to the direction of the wind force.

It can be shown by a mathematical treatment that this condition is fulfilled, if the gyroscopic stability factor (SG) exceeds unity.  This demand is called the gyroscopic stability condition.  A bullet can be made gyroscopically stable by sufficiently spinning it.

As the spin rate decreases more slowly than the velocity, the gyroscopic stability factor, at least close to the muzzle, continuously increases.  Thus, if a bullet is gyroscopically stable at the muzzle, it will be gyroscopically stable for the rest of its flight.

Q. OK, that's complex.  Simple question: Can I fire M193 ammo in my 1:7 or 1:9 twist barrel?

Yes.


M193 is essentially a "universal" round; able to be stabilized by barrels with twists between 1:14 and 1:7.  Point of impact will change slightly compared to an M855 zero, so rezeroing is recommended.  Fact: The Scoop from the Army's Ammunition Information Notice (61-01) "INTERCHANGEABILITY OF 5.56MM BALL, TRACER AND BLANK AMMUNITION."

It is acceptable to use M193 and M196 ammunition in training in M16A2, M16A3 rifles and M4 and M4A1 carbines (16 percent range reduction).  Substituting between types of ammunition during firing is not recommended.

Q. Can I fire M855/SS-109 in my 1:12 twist barrel?

Yes, but...


...it won't be stabilized properly and after 90-95 yards, it will typically veer off in a random direction.  You often won't hit paper at 100 yards.  Though it won't hurt your rifle to fire this ammo, it is not recommended.  Military manuals warn that it should only be fired in 1:12 twist barrels in a "combat emergency."  Fact: The Scoop from the Army's Ammunition Information Notice (61-01) "INTERCHANGEABILITY OF 5.56MM BALL, TRACER AND BLANK AMMUNITION."

"Cartridges M855 and M856 ammunition are extremely inaccurate when fired in the M16 and M16A1.  The M16 and M16A1, with their 1:12 twist, do not impart enough spin on the heavier M855/M856 projectile to stabilize it in flight causing erratic performance and resulting inaccuracy.

Therefore, while safe to fire in M16 and M16A1 they should only be used in an combat emergency and then only for close ranges 91.4 meters (100 yards) or less."

Offline White Israelite

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Re: .223/5.56 CALIBER GUIDE: RECOMMENDED READ
« Reply #2 on: December 23, 2007, 10:14:33 PM »
Q. Will M193 be accurate in a 1:7 or 1:9 twist barrel?

It may be marginally less accurate due to the fast twist rate, particularly in 1:7 twist barrels.  Unless you're trying to use these rounds for benchrest shooting, though, it shouldn't be enough to matter.

A bullet's flight is disrupted slightly as it leaves the barrel and after traveling some distance, will "settle down" into an even spiral, similar to a thrown football.  The faster a bullet is spinning, the longer it takes to settle down.  The most accurate twist rate for any length of bullet will be just a bit faster than what is required to stabilize it for its entire flight path (1.3 SG).  But note that bullet quality plays a much bigger part in this equation.  A uniform bullet will spin true; a non-uniform bullet will wobble and be inaccurate.  As a general matter when shooting M193 or M855 (as opposed to match ammo) its better to err on the side of a faster twist rate.  Regardless, both 1:9 and 1:7 twists seem to shoot M193 and M855 very well.

Q. Won't JSP and JHP rounds be safer indoors?  Don't I have to worry about FMJ rounds going through walls and hurting my family or others?

 You always have to worry about it, of course, but even FMJ 5.56 rounds will have less wound potential after penetrating a wall than even 9mm handgun rounds.  Generally after passing through an interior wall or two, 5.56 bullets will have lost enough velocity that resulting wound damage would be greatly diminished.  It should be noted, however, that all of the above bullets are still potentially deadly to those on the other side of a wall, so plan accordingly.  Interior walls are concealment, NOT cover.

Fact: Evidence increasingly shows that 5.56 FMJ rounds like M193 and M855 are not the over-penetration risk they have often been though of as.  In interior wall tests, 5.56 rounds have less wounding potential after wall strikes than any common 9mm or above handgun ammunition and/or 00 Buck shotgun loads. Q. I'm concerned about roving packs of zombies driving automobiles after the end of the world as we know it.  Since, as everyone knows, you have to make headshots to kill zombies, what ammo should I be using to defeat zombies in automobiles?

Without commenting on the wisdom of engaging roving packs of zombies without adult supervision, the best performing rounds, in terms of penetration of 6mm laminated front windscreen auto glass and other automobile structures, are probably the Federal Tactical 55 and 62 grain bonded JSP (LE223T1 and LE223T3).

Be aware, however, that these rounds, topped with Speer's Trophy Bonded Bear Claw bullet, are designed for penetration and generally do NOT fragment in CQB circumstances.

Unfortunately, Federal Tactical ammo is LEO-only, and while the Trophy Bonded Bear Claw bullet is available in hunting loads and as a reloading component in the 55gr weight, the 62gr version appears to be available only in the Federal Tactical line.  TBBC bullets are also extremely expensive, as they are a high-end, low-volume-production item.




Federal Tactical JSP.   Q. So are heavier rounds dead for self-defense purposes?

Not really, no.


In fact, some more recent work suggests that some heavier, lower velocity rounds are superior in terms of wound ballistics.  Current tests of newer, magazine sized 75, 77, 87 and even 100 grain rounds show faster yaw in ballistic gel and much more dramatic fragmentation than M855.  Some 75gr open-tip (i.e., JHP) match bullets have performed very well in law enforcement use over the past 5 years or so.  Additionally, 77gr open tip match bullets seem to be performing very well for the US military in combat operations since September 11th.  Also showing great promise is the 87 gr P.R.L. match round.

Some of these heavier bullets, probably because of their length, maintain their fragmentation down to below 2100 fps and as a result have a much longer range of fragmentation, out to as far as 300 yards.

The flip side is that these heavier bullets will require at least 1 in 7" twists for proper stability, are more expensive than 55 gr. FMJ, and some types aren't widely available as of this writing.

Some of the heavier bullets can offer superior performance, but at an increased cost. In the meantime M193 is probably still your best bet for bulk defensive ammo. Do take note: this does not mean that all heavy rounds are good terminal performers. Bullet construction is far more important than pure weight or velocity.

Perhaps most promising, however, is the 77 grain Nosler NATO loading from Black Hills. (Not to be confused with the 77 grain Sierra Match King which has a longer neck). This particular round has a very short neck, high fragmentation and wonderful muzzle velocity. 

 

Fact: Black Hills loaded 77 gr. MatchKing bullets have already seen extensive combat use by US military special operations units over the past several months.  Additionally, there are reports that the Hornady 75 gr. TAP has been successfully used by certain U.S. military units for the past few years.

Opinion: Some reputable testers have described the Black Hills 100 gr. round as the "most impressive performing .223 round we have ever tested."  Unfortunately, despite excellent close-range performance, this experimental bullet was dropped due to concerns of over-pressure loads and "rainbow-like" trajectories at ranges beyond 100m.

 

 

 

 

 

 

 

Fact: From a 16" barrel the 77 grain round tested above was still at 2400-2450 fps at 200 meters--and still fragmenting.  The 100 grain round was still fragmenting at 2100fps at 200 meters from a 16" barrel.

Q. What about using Wolf in defensive roles?

 Probably not the best idea.

Wolf is generally underpowered for a Mil-Spec 5.56mm round and velocity, so critical to wound profile in FMJ rounds, suffers as a result. Additionally, the gilding-metal jacket used on Wolf bullets is thicker and therefore more resistant to fragmentation.

In our gel tests, fragmentation of 55 grain FMJBT Wolf and wound volume were both lacking, and we wouldn't recommend it for defensive purposes, particularly not where at least M193 is available at a reasonable cost.


Unfired Wolf and a Wolf FMBTJ round after a close encounter with ballistic gelatin at 2885 fps. The round was fired from a 16" barrel at a mere 16 feet and still did not exhibit substantial fragmentation.

Q. Will M193/M855 penetrate a bulletproof vest?

 That depends.

Bulletproof vest standards in the United States are set and administered by the National Institute of Justice (NIJ), the research and development branch of the Department of Justice (DOJ).  The NIJ does a variety of studies including everything from testing stun guns and facial recognition technology to proposing the best communication equipment for law enforcement agencies.  NIJ standards for Bulletproof vests and gear are defined in the new "Ballistic Resistance of Personal Body Armor," NIJ Standard-0101.04.

Generally speaking Type III-A armor is the about all that one can expect to encounter concealed.  If you don't see armor, you know it's not type III or IV as Types III and IV are both so bulky as to have to be deployed as tactical vest type armors.  Types III and IV require the use of "rifle plates" to stop rifle rounds.  In general Type III armor employs a steel rifle plate over the chest.  Type IV armor uses ceramic plates.

M193 and M855 at anything greater than 2200 fps will generally defeat all body armor up to and including Type IIIA.  How much damage those rounds will do AFTER penetration is guesswork.  In shorter barrels (14.5" and below) that damage is likely to be limited and wound profiles in such instances will resemble .22LR hits.  With higher velocities it's still hard to imagine explosive fragmentation at anything but point blank range but M193 and M855 will certainly defeat all soft armor.

It is worth noting that Type IV armor is only required to withstand ONE hit in the specification.  Many ceramic armor plates are designed to shatter on the impact of a round and lose their ballistic protection as a result.

(As a data point, one test on Chinese steel core 7.62×39mm ammo against a sheet of auto glass, in front of two pieces of sheet metal, two pieces of level IIA body armor, heavy denim, penetrated all barriers and then into the gelatin four inches).



Left: Type IIIA body Armor,  Right: A Type III rifle plate struck with two rounds of:
M193 (upper right) M855 (Lower Right) 7.62 NATO (Left) at 25 feet.
(Plate photo courteously provided by and Copyright BulletProofME.com Body Armor)

 Fact: NIJ's first standard, 0101.00, Ballistic Resistance of Police Body Armor, was published in March 1972.

A revised standard, STD-0101.01 was published in
December 1978.  In March 1985, NIJ amended the standard, issuing STD-0101.02 to take into account armors' susceptibility to angle shots and multi-shot assaults.  STD-0101.03 was released in 1987. Ballistic Resistance of Personal Body Armor, NIJ Standard-0101.04 was published in 2000 and is the first revision in 13 years.

NIJ Standard-0101.04 establishes six formal armor classification types, as well as a seventh special type, as follows:

Type I (.22 LR; .380 ACP).  This armor protects against .22 long rifle lead round nose (LR LRN) bullets, with nominal masses of 2.6 g (40 gr), impacting at a minimum velocity of 320 m/s (1050 ft/s) or less and against .380 ACP full metal jacketed round nose (FMJ RN), with nominal masses of 6.2 g (95 gr), impacting at a minimum velocity of 312 m/s (1025 ft/s) or less.

Type II-A (9mm; .40 S&W).  This armor protects against 9mm full metal jacketed round nose (FMJ RN) bullets, with nominal masses of 8.0 g (124gr), impacting at a minimum velocity of 332 m/s (1090 ft/s) or less and
.40 S&W caliber full metal jacketed (FMJ) bullets, with nominal masses of 11.7 g (180 gr), impacting at a minimum velocity of 312 m/s (1025 ft/s) or less.  It also provides protection against Type I threats.

Type II (9mm; .357 Magnum).  This armor protects against 9mm full metal jacketed round nose (FMJ RN) bullets, with nominal masses of 8.0 g (124gr), impacting at a minimum velocity of 358 m/s (1175 ft/s) or less and
.357 Magnum jacketed soft point (JSP) bullets, with nominal masses of 10.2 g (158 gr), impacting at a minimum velocity of 427 m/s (1400 ft/s) or less.  It also provides protection against Type I and Type IIA threats.

Type III-A (High Velocity 9mm; .44 Magnum).  This armor protects against 9mm full metal jacketed round nose (FJM RN) bullets, with nominal masses of 8.0 g (124 gr), impacting at a minimum velocity of 427 m/s (1400 ft/s) or less and .44 Magnum jacketed hollow point (JHP) bullets, with nominal masses of 15.6 g (240 gr), impacting at a minimum velocity of 427 m/s (1400 ft/s) or less.  It also provides protection against most handgun threats, as well as the Type I, II-A and II threats.

Type III (Rifles).  This armor protects against 7.62mm full metal jacketed (FMJ) bullets (U.S. military designation M80), with nominal masses of 9.6 g (148 gr), impacting at a minimum velocity of 838 m/s (2750 ft/s) or less.  It also provides protection against Type I through III-A threats.

Type IV (Armor Piercing Rifle). This armor protects against .30 caliber armor piercing (AP) bullets (US military designation M2 AP), with nominal masses of 10.8 g (166 gr), impacting at a minimum velocity of
869 m/s (2850 ft/s) or less.  It also provides at least single-hit protection against the Type I through III threats.

Fact: Take a look at the very extensive history of body armor and the testing methods at the NIJ's official standard publication site.  http://www.ncjrs.org/txtfiles1/nij/189633.txt

Q. My department is considering using 10" or 11.5" barrels for our ARs. They are so cool, and everyone knows that all the real go-fast, high-speed, low-drag operators use SBRs. Plus, Robert DeNiro uses one in "Heat." What's the best ammo to use to poke big holes in the bad guys with these?

We dislike this question. We dislike it because of its premise. The premise is that 10" or 11.5" barrels are good choices for law enforcement or defensive use. We strongly disagree with this premise. Some of us actually dislike even 14.5" barrels, in fact.

The primary wounding mechanism for .223 and 5.56 ammunition is fragmentation. The primary factor in fragmentation is velocity. The primary velocity booster is barrel length. 11.5" barrels barely bring milspec (NATO) 55 grain FMJ to 2700 fps (the critical fragmentation threshold for many FMJ .223 rounds). Accordingly, any distance at all drops the rounds below fragmentation velocity. 10" barrels are unlikely to ever get rounds above fragmentation velocity at all.

If you are saddled with a department mandated SBR we recommend the following:

1. A marathon letter writing campaign citing the Ammo Oracle often persuading the powers that be to see reason and potentially save lives by giving you REAL weapons, not toys.

2. Use heavier rounds known to fragment at lower velocities and do more tissue damage such as:

68 grain Hornady Match OTM
69 grain SMK OTM
75 grain Hornady TAP
77 grain Nosler OTM

Obviously, you should probably have a 1:7" twist.

Under no circumstances should you take comfort in the assurances your armorer gives you that the latest soft point or hollow point law enforcement specialty round will solve the problem. Most likely it will not. Soft point and hollow point rounds lack penetration even at high velocity. Because they are not prone to yawing or fragmentation lower velocities will not increase penetration as with many fragmenting rounds.

.223 and 5.56 Ammunition Testing
    Q. Is Gelatin testing accurate or what?


 Many scholarly studies have shown that, for the most part, properly chilled ballistic gelatin simulates average penetration in tissue. Obviously, softer tissue (lungs, abdomen) will have more penetration while denser tissue (muscle) will exhibit less. For the most part, however, gelatin testing is a good indicator of how a round will perform on average in tissue. Built into the expectations for a successful gel test are margins for performance. 12" of penetration as an expectation (the FBI standard) is intended to cover the vast majority of shooting situations. While every ballistic encounter is unique, rounds that perform consistently well in properly prepared and calibrated gelatin can be expected to perform similarly well in actual tissue.

Often we see makers, backyard experts and others shooting things like a rib roast, a slab of beef or other strange food items (our favorite is fruit) and attempting to compare these results to results in human tissue. We also see people comparing deer results with results they expect in humans. "I killed a dozen deer with it... it must be a man stopper."

This is, unfortunately, folly. Deer, to begin with, have SUBSTANTIALLY different anatomies than humans (surprise surprise). The distance in tissue to vital organs is different, bone density is different, the location and strength of CNS structures is different, as is the vascular system. Further, because the CNS structures of deer are somewhat more primitive and less intricate than those of humans, they are far less fragile in some places, far more fragile in others. What works in deer may or may not work in humans. The same goes for hogs, varmints, pigs, dogs, zombies (headshots only please), and aliens (particularly grey skins- go for the big eyes, not center mass).

Likewise shooting a side of beef isn't good for much but making hamburger.

Why gel? Gel can be made consistent. We can compare apples to apples with gel and see that one round performs in it better than another. It is transparent and so we can measure ACTUAL wound cavities rather than just a gaping exit hole. Fragments are left behind in gel much as in tissue so we can measure fragmentation, and finally, properly calibrated gel has been linked by at least six studies to performance in human tissue. This bears repeating because many people choose to ignore this. Performance in properly calibrated gel simulates very closely performance in human tissue in test after test.

The trick with gel is asking "was the gel properly prepared and shot?"

When looking at test information focus on several factors:

1. Was the gelatin calibrated right before testing? Calibration is accomplished by firing a .177 cal BB into the gel and measuring penetration. Proper penetration indicates that the gel is of a known density and can be used to measure penetration accurately.

2. Was the gel prepared properly? Proper gel preparation is important to gel testing and professional experimenters will always note that the gel was prepared according to particular specifications.

3. Was the gel stored properly. Proper gel storage is also important and professional experimenters should note how their gel was stored prior to shooting.

Q. Where can I find reviews of various types of ammo?

 Besides the AR15.com  Ammunition forum, which will often have information on the ammo types currently available from distributors, check here:

http://www.aaconsult.com/ammoreview   

Q. Why should I test new-production ammo?  It should work, shouldn't it?

It should work fine and it usually will, but any company can (and has) put out bad batches of ammo.  Plus, some rifles are marginal and you may find that some ammo isn't reliable in your rifle.  Always test your ammo before committing it to storage or duty use.   

Fact: Testing and reporting results is a great way to contribute to the community.  Good range reports help us all spot good and bad ammo.

Q. How do I make a professional looking/sounding range/ammo report of some ammo I liked/hated?

 The best range reports will list:

Conditions: Temperature, humidity, wind, altitude. (These are very important)
Type of Ammo: Manufacturer, weight, bullet type (M193/M855 hollow point, boat tail, full metal jacket, etc.), year of manufacture, lot number (lot number is important).

Results: Velocity, size of groups, range of the target.  (You'd be surprised how many people report 1" groups and then fail to report that they were shooting at 25 yards).  Groups should be at least 5 rounds, preferably 10.  If you are using a chronograph, velocity should at least include a list of all the rounds timed and if you have the time, average, high, low and standard deviation.

Try to use the standard chronograph distance: 15 feet from the muzzle.  This makes it very easy to compare your results to military and other tests which use 15 feet as a standard.  Technically, M855 is measured from 78 feet according to the spec (no, we have no clue why) but it's easy to adjust 15 foot figures to 78 feet and 15 feet is probably much safer for your chrono screens.

Other observations: Excessive flash, slow primers, reliability, any failures or malfunctions.

All these details will permit other shooters to assess the ammunition you tested. 

 

Opinion: A good example range report (courtesy of AR15.com's own t38tallon):

Here are the results of my testing of Lake City XM193
(Lot-1) ammo.


Firearm-Bushmaster M4, 14.5" barrel, (1-9")
Brass Headstamp-00, 01
Temperature-62-65 deg F
Altitude Above SL-100'
Number of shots in test-10
Target Distance-100Y
Sights-Open from bench rest
Velocity Measured with a Chrony @ 10' from muzzle.
High Velocity-3087 fps
Low Velocity-3030 fps
Average Velocity-3053 fps (10 shots)
Accuracy-Good, at approx 2" Q. What is B & T Ammo Labs?

B & T Ammo Labs is AR15.com's home grown ammo lab. It does gelatin and performance testing primarily on rifle ammo. It was formed originally by AR15.com's Derek F. and Tatjana out of an increasing need for terminal performance information on newer and heavier rifle rounds in .223 to determine the ideal self-defense loading to replace M193.

Now B & T Ammo Labs serves as a clearing house for ammo testing information, terminal performance review and a forum for reader ammo testing contributions. It is dedicated to brining terminal performance information and ammunition and other equipment reviews to the AR15.com community.

B & T Ammo Labs is happy to take reader submissions. Mail them for more info at: [email protected]

   

Visit: B & T Ammo Labs.

Selection of .223 and 5.56 Ammunition.
     Q. Do I want SS-109 or M855 then?


 Between the two?  Probably M855.  As noted you never know for sure what your going to get with loads that are only marked SS-109.  M855 shouldn't cause you any problems and is generally well liked by AR15 shooters.  Don't worry if ammo is labeled as SS-109/M855.  That should be M855 spec.   Note: M855 is effectively a implementation of the SS-109 interoperability standard (so all NATO members can shoot each other's ammo).  The US, however, requires stricter standards in M855 and as a result, M855 manufacturers generally load their rounds to hit at least 3000 fps at 78 feet from the muzzle.  The SS-109 specification had a lower 2985 fps requirement and British SS-109 rounds are slower still (2700-2800) to deal with the SA80 rifles.

Opinion: Some British SS-109 reportedly is underloaded (in order to permit proper operation in the L-85 Bullpup also called the SA-80 rifle) and therefore causes some short cycling in Bushmasters and Colts and isn't likely a good choice for emergency or critical use ammo.

Q. What if I want more punch? What should I move up to from 5.56mm?

If you are looking for more effective terminal performance you probably have to move up to 7.62 NATO or a 12ga shotgun.  In 12ga, the Choke #00 "Precision Bonded" Buckshot appears to be among the best performers.  Brenneke slugs are a good choice when penetration through intermediate barriers is required.  Moving up to a 16-18" rifle chambered for 7.62 NATO might be a good alternative--as long as ammunition is carefully selected for optimal performance.  In 7.62 NATO, the bullets with the best terminal performance include plastic tip bullets such as the 150 gr Nosler Ballistic Tip and 155 gr Hornady AMAX (they have dramatic fragmentation and usually maintain 13-15" of penetration in gel testing), as well as the 165 gr Sierra GameKing softpoint.  Obviously, any of these combinations will be better for defeating barriers--particularly windscreen autoglass--than 5.56 mm, and accordingly should be more carefully deployed with an eye towards indoor overpenetration.




5.56 LC'00 (left) and 7.62 NATO Hirt (Right)

Q. Isn't 5.56 too dangerous to use indoors?  Shouldn't I use a pistol or shotgun instead?

Virtually any kind of ammo, with the exception of light bird shot, will easily penetrate typical wall construction (two layers of wall-board separated by 3 to 4 inches of space). Testing has shown, however, that after penetrating a typical interior wall, a 5.56mm projectile will have less wounding potential than most common handgun or buckshot loads. This is true because the low mass of the bullet sheds velocity quickly, and velocity is its key wounding component. This doesn't mean that 5.56mm ammo isn't still potentially deadly, but that the severity of an injury is likely to be less from a 5.56mm bullet than from a 9mm, .40, .45, or #00 buckshot round. What is important is not the degree to which these rounds penetrate, but their "ex post lethality" or their lethality AFTER encountering wallboard or other cover/concealment.

The difference is so significant that the FBI and other ballistic experts recommend that law enforcement transition to handguns to "dig suspects out" of cover because of the superior penetration and wounding ability of handgun rounds over 5.56 or .223.

This, along with the increasing number of lawsuits from "friendly fire" submachine gun victims and 5.56mm's ability to penetrate ballistic vests, are some of the reasons that many SWAT teams are transitioning away from the 9mm MP5 and selecting 5.56mm carbines instead.

This is understandable given the longer barrel length and therefore higher velocity and consequently higher penetration of handgun rounds in submachine guns.

If our experience on the forums are accurate, most shot gunners and submachine gun fans receive this news poorly. It does seem counterintuitive since 5.56mm is a "high powered round." All we can say to this is that the FBI FTU fired hundreds of rounds through carefully constructed wall sections and then into gel. Ignore these results at your own peril.



Fact: Interestingly enough, in FBI Firearms Training Unit tests show that submachinegun and handgun rounds penetrated more on average than .223/5.56mm rounds in typical interior construction and tissue.

Opinion: Generally high velocity rifle rounds fragment so readily that over-penetration in an urban (indoor) setting is LESS dangerous than with handgun or submachinegun rounds like 9mm, 10mm, .40S&W, etc.  5.56 FMJ rounds will do more penetrating than JHP and JSP rounds but still are generally safer for interior use- insofar as bystanders are concerned.

Q. What is "SHTF" ammo?  What is "TEOTWAWKI?

 "SHTF" is an acronym for the "[censored] Hits The Fan," meaning a natural disaster, a catastrophic breakdown in civil service, a military takeover, a New World Order, or an invasion by brain eating zombies that makes life an exercise in "every man for himself."  (Also known as "The End Of The World As We Know It" or TEOTWAWKI--easily characterized as akin to a third NSYNC and Britney Spears tour.)  Of course, depending on your view of the goodness (or lack thereof) of man, you may or may not consider a SHTF scenario likely.  It is worth noting, however, that the New York blackout, the LA riots, earthquakes, and other fairly recent breakdowns in social fabric have all made the prepared feel pretty good about having a little SHTF ammo around.  It all depends on your tin-foil hat quotient™.

Regardless of your politics, SHTF ammo is a good term to use to refer to ammo stored away (perhaps underground), "just in case."  Criteria for good SHTF selections are obviously: Storage/durability, cost, defensive performance as an antipersonnel round, reliability, reliability, and reliability.  This is ammo that--quite simply--just has to go bang every single time without fail.

As a general matter, new manufacture (i.e., less than 3 years old when you buy it) military-spec ammo is probably the best for SHTF use.  The bullets and primers are sealed, they may have flash reducing powder formulas, they are loaded a bit hotter than commercial ammo, designed for storage under military (read: non-ideal) conditions, non-corrosive, cheap ($0.10 - $0.14 a round if you buy in quantity), and have good antipersonnel properties.

SHTF sort of supposes that you will be a lone actor, that engagements will be inside of 150 yards, and that you'll be in an urban or suburban environment.  Of course, we tend to like M193 for these purposes.  M193 has the added benefit of working in a wide variety of weapons and rifling twists, making it a good trade commodity, and flexible in whatever 5.56 weapon you're likely to get your hands on.


Opinion: Don't buy anything from late 1999.
Some purists might tell you that anything of late 1999 manufacture is likely to suffer from quality control issue because of the rush of many manufacturers to meet Y2K demand.


 

 

 

Opinion: You should probably avoid surplus ammo since there is no telling how it has been stored over the last many years.



Opinions (Pro and Con):
5.56 is not good SHTF ammo.
5.56 doesn't penetrate enough, it doesn't defeat light cover and the lack of fragmentation at range of FMJ rounds means that 7.62 is a better choice.

5.56 is best for SHTF.
5.56 is light, more of it can be carried, light recoil means faster shot recovery for follow-ups and it performs just fine inside of 200 meters.  Since SHTF engagements aren't likely to exceed that there is no reason to use 7.62.

Offline White Israelite

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Re: .223/5.56 CALIBER GUIDE: RECOMMENDED READ
« Reply #3 on: December 23, 2007, 10:23:04 PM »
Q. What is the best M193 to get?

Clearly you want to find new production ammo.  Again, surplus is great stuff for practice and fun but for "serious" ammo you will want to find ammo that's less than 36 months old.

In the M193 class it's pretty generally agreed that the best manufactured ammo is from the Lake City Army Ammunition Plant located in Independence, Missouri.  2000 manufacture Lake City (LC'00) and 2001 Lake City (LC'01) is outstanding ammo.  It's assembled at the Lake City plant and boxed up by Federal.  It is accurate for M193, is loaded quite hot and has great velocity as a result and it seems flawlessly reliable.  Lake City ammo also has a reputation for storability and reliability.  Several AR15.com members have tested 15 year old Lake City and it often turns out to perform better than newly manufactured commercial ammunition.  It's very much the gold standard of M193.


Lake City XM193.

Winchester Q3131 and Winchester Q3131A are considered close seconds, perhaps indistinguishable seconds to Lake City M193.  Both are Mil-Spec M193 but many AR15.com members have reported that LC is loaded a bit hotter.

Q3131 is the U.S.-manufactured Winchester M193, but since 2000 (and coinciding with the transition at the Lake City plant which left it shut down), Winchester's M193/Q3131 ammo has all gone to the military.  Due to the demand during the Y2K scare, Winchester had subcontracted some of its civilian M193 production to IMI.  Winchester has continued this contract, and the IMI-produced ammo is labeled Q3131A by Winchester.

Q3131A also is somewhat famous for its shining new cases.  Lake City kept their production costs down by not polishing their brass before shipping.  Since the military was their primary customer why bother making the rounds "pretty?"  LC often has spots and other material on their cases (not that this seems to impact its stellar performance at all).  Q3131A is much prettier looking, though still not as sparkling clean as commercial ammo that's been tumbled clean.  XM193 also comes in boxes with plastic spacers.  Many people find these annoying.

As you can see, the complaints about the two types of ammo are so trivial as to be almost not worth considering. 

The Lake City Shutdown Story
(courtesy of Dave_G):
Alliant Techsystems assumed control of operations at Lake City AAP on April 3, 2000.  There was a lot of stuff laying around in the warehouses, components, loaded ammunition and what have you, that had been produced under Olin's operations.  Alliant wanted to get rid of all Olin materials, so they approached Federal.  About September, several ammunition distributors were approached by Federal and offered the XM193 5.56mm ammunition, produced in 2001.  Millions of rounds were sold, packaged in generic white boxes with the Federal logo on them.

Some of this ammunition may have been Olin-produced loaded ammunition of 2000 vintage that was never packaged and shipped.  It was just stored in those great big bins awaiting the orders that never came.  Some may have been new ammunition loaded from leftover Olin-produced components.  Still more may have production run startup and stop overruns.

In December, Alliant completed acquisition of Blout's Sporting Equipment Group, including Federal Cartridge.  Now Alliant was both operating the plant and selling XM193.

Then the Army steps in and halts deliveries.  The word is that it is over liability issues.

All the headstamps on the Federal XM193 ammunition mean is that the cases are stamped LC01 and were intended for use in 2001 ammunition production.  Cases intended for 2001 production can be manufactured in prior years and stored.  You should not consider that the XM193 headstamps have any meaning at all other than to identify the cases as having originally been intended for production of 2001 Lake City ammunition.

Opinion: Some lots of 1999 Winchester Q3131 (but not Q3131A) had quality control problems.  As a result many AR15.com members avoid Q3131 entirely and prefer Q3131A.

Opinion: Some lots of LC'00/LC'01 aren't properly sealed. Currently it appears that Lot 7 and some of Lot 6 is not properly sealed around the case necking.

Q. But aren't all M193 rounds the same?  It's a standard specification, right?

 Yes and no.

While several parameters are set out for bullet size shape and construction, there is still room for differences. The shape of the boat tail, the thickness of jackets and the type of cannelure all vary with manufacturers.

Types of powder, materials and manufacturing process will all contribute to the differing characteristics of one load or another. Additionally, variations between lots from the same manufacturer might depend on what materials were available at the time of manufacture or what the humidity in the plant was during manufacture.

The best way to decide on the type of M193 (or any ammo for that matter) you prefer is to make an educated guess based on feedback of AR15.com members and other sources before shooting some in the weapon of your choice to see how it performs.

Q. What is with this goo and the dings on my Lake City Rounds?  What is this discoloration on the necks of my Q3131A?  Did someone take a blowtorch to it?

Lake City doesn't bother to polish ammo after it's loaded. Occasionally you'll see dings or excess sealant on the casings of Lake City ammunition, particularly the Federal XM193 that Lake City has produced of late.  Sometimes the ammo looks downright beat up.  It's generally not anything to be concerned about and shouldn't impact performance.  Still, most distributors will offer to take the ammo back if it's in that condition.  Check to see if your vendor has a return or satisfaction guaranteed policy if you're really worried about pretty ammo.  You can also send it to the AR15.com staff "Ugly Lake City Disposal Facility" and we will be happy to render each and every round safe.  J

Just about all necked rounds use a heat process called "annealing" to shape the neck of the casing.  Producers of military ammo don't bother to spend the extra time and effort in production to polish the brass after annealing, unlike most commercial ammo.  The result is that discoloration that makes it look like someone took a blowtorch to the ammo.  Don't worry, it won't impact the performance in any way.

Of course, you probably do not want to use ammo that is more severely damaged. Avoid ammo with significant deformities on or above the neck.


AR15.com user Greenhorn found this round shipped in a new box.
The damage on the neck of the case probably makes this dangerous to fire.


A lovely box of Q3131A from
www.ammoman.com.

Q. What is the best M855 to get?

 The name most often tossed around as the best M855 is IMI.  Israeli Military Industries are the same people who make Q3131A and their M855 is apparently just as reliable.  Additionally, you can find it newly manufactured.  Lake City and Winchester both produce M855, but it is almost never available anymore, and certainly not as new-production.  The only exception is that Winchester makes M855 available to police departments.  Occasionally, small quantities of this gets traded back to ammo dealers, and become available for civilian sales.   

Q. Where can I get some M995 AP?

Unless you are in the military, you probably can't.  This ammo is a fairly new item that is rare even in the military, as it is considered a "special issue" item.  It is illegal for licensed dealers to sell AP ammo (except M2) to civilians and no components are available for reloading.

It will probably be many years before any M995 ammo is "demil'ed" (demilitarized, meaning disassembled) and components released.  That's assuming AP bullets are still legal to possess as components at that time.

Be careful of scams.  One of the authors has personally seen vendors selling Bosnian SS-109 ammo, which uses black tips instead of the more common green, as "armor piercing", implying that it is M995.  It isn't.  Another vendor was selling stripper clips (10 rounds) of US-made M855 with black-painted tips (likely painted by the vendor himself) for $5/clip.  This vendor also heavily implies that this is M995, though I don't believe either vendor is familiar with that designation.  Be very careful before spending your hard-earned cash...

Fact: The 5.56 AP round penetrates 12mm armor plate of 300 HB at 100 meters.

Q. Should I leave two tracers at the bottom of my magazine to tell me when I'm out of ammo?

This depends.

Do you also want to tell your enemy both where you are and that you are out of ammo?

While technically tracer rounds are only supposed to "light up" a few dozen yards from the shooter, in actual use, many tracer rounds ignite right out of the barrel.  This, combined with muzzle flash, is a positional dead giveaway.

Tracers are best left for machinegunners, or for squad/platoon leaders to use as marking rounds to direct the rest of the squad/platoon to a target.

Q. Isn't shooting tracers bad for my weapon?

 Well, actually they can cause problems if you use them excessively.  Consider this from FM 23-9:

    Soldiers should avoid long-term use of 100-percent tracer rounds. This could cause deposits of incendiary material/chemical compounds that could cause damage to the barrel. Therefore, when tracer rounds are fired, they are mixed with ball ammunition in a ratio no greater than one-to-one with a preferred ratio of three or four ball rounds to one tracer round.

M196 tracers use strontium nitrate, strontium peroxide, barium peroxide, lead peroxide, magnesium powder, calcium resinate, and PVC for their tracer compound.  The ignition primer is barium peroxide, magnesium, antimony trisulfide, and graphite.  M196 tracer composition doesn't have much of a shelf life and it gets spotty after enough years.  M856 tracers are much more impressive.

When fired, small fragments of tracer composition are likely to be dislodged and left behind in the barrel, sometimes lit, sometimes not.  As tracer composition burns slowly (compared to powder) and hot (2000 degrees F) you really don't want it in the barrel in any great quantity for long.

Apparently the compounds can leave traces of ammonia, though not necessarily enough to be a problem.

Given this, it's probably a bad idea to have tracers in the last slots of your magazine also. "Tracer goo" could sit there awhile if you shoot your last mag and take your weapon home before cleaning.


Q. Can tracers cause fires?

You bet.

Be very careful of any underbrush or vegetation, especially in dry weather.  Tracers are banned in California and a few other states due to the extreme fire hazard they pose when used, and it is not at all uncommon for infantry soldiers to inadvertently start fires when using tracers in training.

Remember: Only you can prevent forest fires.   



That's all I was able to recover from the guide guys, hope this helps.