M4 "Loses" Dust-test

[DocGKR]

77 gr FMJ (head stamp: NWM 67) and 68 gr FMJ (head stamp: IVI 69) loadings were made for the Stoner 63A for use by NSW in Viet Nam.

When tested from an M16A2:

77 gr FMJ: vel = 2874 f/s, pen = 19.2”, neck = 5.1”, bullet fragmented like M193

68 gr FMJ: vel = 3014 f/s, pen = 14.6”, neck = 2.8”, bullet flattened but did not fx

Bottom line--there is a lot better stuff available now.

[ddemis]

OK, since I have never had to drop a Haji or anyone else with my M-4 I can't speak from personal exp. but I have gathered a lot from this thread. It seems the 5.56 with 55gr ammo did a good job at stopping the fight.Enter the 62gr green tip designed to punch through body armor. It seems to do a great job at going through doors, walls,cars etc. But when it hits a bad guy it punchs straight through with less fragments and exits often leaving a wounded bad guy on the loose, wrong or right?

[DocGKR]

There seems to be some misconceptions regarding terminal performance issues, so at the risk of some thread drift, here is some info that may help.

Keep in mind that the 5.56 mm NATO 62 gr SS-109/M855 gr “Green Tip” full metal jacket (FMJ) was designed over 20 years ago as linked machine gun ammunition to be fired from the FN Minimi/M249 SAW while engaging enemy troops wearing body armor during conventional infantry combat at distances of several hundred meters; it was not originally intended for use in carbines or rifles. Unfortunately, recent combat operations have highlighted terminal performance problems, generally manifested as failures to rapidly incapacitate opponents, during combat engagements when M855 is fired from 5.56 mm rifles and carbines. The disturbing failure of the 5.56 mm caliber to consistently offer adequate incapacitation has been known many years. Dr. Fackler’s seminal research at the Letterman Army Institute of Research Wound Ballistic Laboratory during the 1980’s illuminated the yaw and fragmentation mechanism by which 5.56 mm FMJ bullets create wounds in tissue. If 5.56 mm bullets fail to upset (yaw, fragment, or deform) within tissue, the results are relatively insignificant wounds, similar to those produced by .22 long rifle bullets--this is true for ALL 5.56 mm bullets, including both military FMJ and OTM (open tip match) and civilian JHP/JSP designs used in law enforcement. As expected, with decreased wounding effects, rapid incapacitation is unlikely: enemy soldiers may continue to pose a threat to friendly forces and violent suspects can remain a danger to law enforcement personnel and the public. This failure of 5.56 mm bullets to yaw and fragment can be caused by reduced impact velocities as when fired from short barrel weapons or when the range to the target increases. Failure to yaw and fragment can also occur when the bullets pass through only minimal tissue, such as a limb or the chest of a thin, small statured individual, as the bullet may exit the body before it has a chance to yaw and fragment. In addition, 5.56 mm bullets are less effective when intermediate barriers, such as walls, glass, and vehicles shield opponents.

For those folks who think the older 55 gr M193 FMJ is a great 5.56 mm load for self-defense, the following quote was written by Dr. Martin Fackler, the man who has done more research on the M193 than anyone else on this planet:

“In 1980, I treated a soldier shot accidentally with an M16 M193 bullet from a distance of about ten feet. The bullet entered his left thigh and traveled obliquely upward. It exited after passing through about 11 inches of muscle. The man walked in to my clinic with no limp whatsoever: the entrance and exit holes were about 4 mm across, and punctate. X-ray films showed intact bones, no bullet fragments, and no evidence of significant tissue disruption caused by the bullet’s temporary cavity. The bullet path passed well lateral to the femoral vessels. He was back on duty in a few days. Devastating? Hardly. The wound profile of the M193 bullet (page 29 of the Emergency War Surgery—NATO Handbook, GPO, Washington, D.C., 1988) shows that most often the bullet travels about five inches through flesh before beginning significant yaw. But about 15% of the time, it travels much farther than that before yawing—in which case it causes even milder wounds, if it missed bones, guts, lung, and major blood vessels. In my experience and research, at least as many M16 users in Vietnam concluded that it produced unacceptably minimal, rather than “massive”, wounds. After viewing the wound profile, recall that the Vietnamese were small people, and generally very slim. Many M16 bullets passed through their torsos traveling mostly point forward, and caused minimal damage. Most shots piercing an extremity, even in the heavier-built Americans, unless they hit bone, caused no more damage than a 22 caliber rimfire bullet.”Fackler, ML: “Literature Review”. Wound Ballistics Review; 5(2):40, Fall 2001

Note--The original AR15 had a SLOW twist of 1/14; as the M16A1 developed, this was changed to a slightly FASTER twist of 1/12. The change in twist rate to the TIGHTER/FASTER 1/7 was made with the M16A2 in order to stabilize the long M856 tracer round, not the M855. Despite folk lore to the contrary, as long as the bullet is properly stabilized in flight, the yaw in tissue is relatively unaffected by barrel twist.

The last several years of OCONUS GWOT operations have provided a tremendous amount of combat derived terminal performance information. The U.S. government gathered numerous experts from a variety of disciplines, including military and law enforcement end-users, trauma surgeons, aero ballisticians, weapon and munitions engineers, and other scientific specialists to form the Joint Service Wound Ballistic Integrated Product Team to conduct a 4 year, 6 million dollar study to assess terminal performance. Very little ACCURATE public information has been released, but you might wish to review: http://www.dtic.mil/ndia/2004arms/session9/minisi.ppt (Warning, this is a VERY large file). The JSWB-IPT identified two issues that significantly alter projectile terminal performance at CQB distances, thus causing differing terminal effects. First, Angle-of-Attack (AOA) variability at impact can substantially wound severity; this factor is more prevalent with certain calibers and projectile types. Testing demonstrated that 5.56 mm is highly susceptible to AOA variations, particularly when using FMJ projectiles such as M193 & M855. For example, with 5.56 mm FMJ, at higher AOA’s, for example 2-3 degrees, bullets had a shorter neck length (NL) and upset rapidly, thus providing adequate terminal effects; at low AOA, like 0-1 degree, the projectiles penetrated deeper than ideal prior to initial upset (ie. long NL) with significantly reduced terminal effects. Note that other calibers were less susceptible to AOA variations than 5.56 mm and OTM’s tend to have less AOA issues than FMJ. The 6.8 mm has proved to have the least AOA inconsistencies of any caliber tested to date. Fleet Yaw is the other significant yaw issue discovered by the JSWB-IPT. Fleet Yaw is the terminal performance variation caused by inherent variability in each rifle. 5.56 mm FMJ had the most Fleet Yaw induced variability of any projectile caliber & type. 6.8 mm had the least Fleet Yaw variations of any projectile caliber & type tested.

What this means is that two shooters firing the same lot of M855 from their M4’s with identical shot placement can have dramatically different terminal performance results: one shooter states that his M855 is working great and is effective at dropping bad guys, while the other complains his opponent is not being incapacitated because M855 is zipping right through the target without upsetting. Both shooters are telling the truth…

To help clear-up any confusion, here are a few illustrative wound profiles for comparison purposes:





The 30 cm/12” line represents the minimum penetration distance necessary to consistently damage vital organs on larger individuals, with shots from oblique angles, and through intervening limbs. The 20 cm/8” mark gives a rough idea of the damage on an unobstructed frontal shot or on shots through thin, malnourished individual.

Mk262 using the 77 gr SMK OTM is built as premium quality ammunition intended for precise long-range semi-auto rifle shots from the Mk12. It is great for its intended purpose and in the military is the best currently readily available option to increase terminal performance with all 5.56 mm carbines. But Mk262 is NOT necessarily the best choice for LE or most military combat use from carbines (Mk18, HK416, M4, FN Mk16 SCAR-L), as Mk262 has demonstrated poor intermediate barrier performance, the inconsistent yaw cycle exhibited by most SMK’s, incomplete water proofing, fragile shelf-life in extreme temperatures, and high cost.

As articulated by recent military testing, what is urgently needed is a JAG approved, law of land warfare legal, environmentally robust, thermally stable combat rifle load with improved terminal performance, yet without the need for the 600+ meter precision accuracy of Mk262 in the Mk12. Such an ideal carbine combat load needs to have a crimped and sealed primer, sealed case mouth, cannelure for reliability in adverse conditions. It must possess acceptable accuracy out to 300-400 meters coupled with good soft tissue terminal performance (early consistent bullet upset within 1 or 2 inches of initial tissue penetration, at least 12 inches of penetration coupled with maximized tissue damage during the first 10 to 12 inches of travel in tissue, along with being “blind to barriers” and not suffering terminal performance degradation through intermediate barriers--especially automobile windshields & doors, and common structural walls (see the 01 June 2006 Marine Corps RFI: http://www.cbd-net.com/index.php/search/show/1087257 for “Barrier Blind” ammunition.) Likewise, the ideal combat ammunition should exhibit minimal AOA and fleet yaw issues. The ammunition should be light and compact enough for the operator to carry an adequate supply of ammunition in magazines of at least a 25 round capacity. The rifle should be similar in size, weight, and ergonomics to the proven M4/M16 weapons. Recoil should be manageable to allow full auto fire when necessary, along with the more usual rapid, aimed semi-automatic fire. What this all translates into is something that looks like:



Take another look at the wound profiles illustrated above--which ones get closest to matching the optimal wounding characteristics? Want to guess which ones have proven most effective in combat?

While there are some very good improved 5.56 mm loads becoming available, none are superior to an equivalently constructed 6.8 mm. In fact the JSWB-IPT wrote: “The best performing systems emphasizing tissue damage, on the average, in this study were of larger caliber than 5.56 mm.” Anybody who has seen the actual data from the 10,000 test shots in 8 calibers, using 53 different systems collected by the JSWB-IPT at 3-10m, 100m, and 300m distances or who has read the original 331 page final draft report dated 12 April 2006, knows the clear and unequivocal best performing cartridge in the JSWB-IPT was 6.8 mm. The JSWB-IPT remarked that: “The 6.8 mm projectile had a near optimal balance of MASS, VELOCITY, and CONFIGURATION to maintain its effectiveness, even at a lower impact velocity.” This was validated by other recent military and law enforcement agency testing—all of which repeatedly have demonstrated that 6.8 mm offers the best terminal performance of ALL assault rifle calibers tested to date. In assessing the end-users request for weapons with increased incapacitation potential, as well as their desire for more easily maneuvered weapons, the JSWB-IPT declared that: “The 6.8 mm performance observed in this test suggests that an intermediate caliber is the answer to the trade-off balance issue.”

I am sure many of you have seen this picture, but it remains a vivid illustration of the advantages provided by 6.8 mm over 5.56 mm:

[Patrick Aherne]

Aww, Doc, all those scientific facts and measurements make my noggin hurt. Why can't we just go back to the '03 Springfield with dum-dum notches carved with pocket knives?

[Heavy Metal]

Thans for the new insight Doc.

That is the first I have heard of Fleet Yaw.

Do you have any working theories as to what causes this?

[Armati]

I think the FM for rifle marksmanship even eludes to the long NL / short NL thing.

It advises controlled pairs for CQC in order to cause a more lethal wound on the follow up shot.

Most any soldier can be trained to kill a 6" dot quickly with controlled pairs. Many can even do it on the move at CQC distances. Some can even kill a 3" dot.

It is a bad assed Hadji that can take two 5.56 rounds to his 6" dot and keep fighting!

I do like the additional penetration the M855 gives. Maybe we could get a steel perpetrator in a heavier bullet? Sometimes you need remind your enemy that there is a difference between cover and concealment.

[variablebinary]

Getting a new weapon fielded will take years. I can’t even imagine what it would take to convince .MIL to adopt a new bullet, especially if there is a mandate on NATO uniformity

From a logistical standpoint (my industry), both are terribly daunting endeavors.

As someone said earlier though, get a more reliable, multi-caliber weapon fielded first, then proceed to evaluate new bullet designs to increase the lethality of said weapon.

[DocGKR]

Fleet Yaw is caused by weapon to weapon variations. Projectile impact AOA variability is caused by bullet to bullet variations. Both appear much more prevalent in 5.56 mm, particularly with FMJ loads, than with larger calibers and match loads. These are clearly multi-factorial problems of multiple etiology including: ammo and weapon design issues, ammo and weapon manufacturing variations, individual weapon wear issues, along with both mechanical function and internal ballistics variances.

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"It is a bad assed Hadji that can take two 5.56 rounds to his 6" dot and keep fighting!"

Happens more than you might think, ask Tony Pryor...

"I do like the additional penetration the M855 gives."

Huh? M855 has very inconsistent penetration, often having too deep an initial upset depth. You'd be much better off with an OTM or one of the new barrier blind loads.

"Sometimes you need remind your enemy that there is a difference between cover and concealment."

That's what M993 is for and why 6.8 mm is so much better than 5.56 mm...

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Variablebinary, I strongly disagree.

[TY44934]

It is a bad assed Hadji that can take two 5.56 rounds to his 6" dot and keep fighting!

I do like the additional penetration the M855 gives. Maybe we could get a steel perpetrator in a heavier bullet? Sometimes you need remind your enemy that there is a difference between cover and concealment.

I agree - but I also believe that the United States will not be fighting the typical low-tech Hadji for much longer. Israel recieved a rude wake-up call during their last war against Hezbolla when they discovered them using much more modern weapons, communications, and gear, and apparently they had actually trained with it (unlike past wars).

I think that not only will our foes from the middle east continue to evolve, but our foes the Chinese will repidly evolve.

What does this have to do with ammo? The US should expect to encounter Chinese soldiers equiped with advanced body armor. Will we be equiped with the right armor piercing 5.56mm ammo & trained to defeat such armor?

Somehow, I do not believe we will be well prepared for that fight.

[jmart]

I think that not only will our foes from the middle east continue to evolve, but our foes the Chinese will rapidly evolve.

The US should expect to encounter Chinese soldiers equiped with advanced body armor.

Where do you think this fight will occur?