M-16/M-4 Bullet Lethality

[Leatherneck]

I could have sworn I remember some recent discussion on this, but I'll be darned if I can find the thread. Here's a Washington Times article, along with some update from one of the guys in my shop.

THE WASHINGTON TIMES
June 16, 2006
Inside the Ring
By Bill Gertz and Rowan Scarborough
Army ammo
The Army recently concluded a $3 million, three-year study to find out what it was told by a group of specialists years ago: The killing power of the M-16/M-4 carbine is good for close combat.
The Army study started after some soldiers in Afghanistan claimed that the 62-grain, 5.56 mm round did not have enough stopping power to kill terrorists in close combat. The complaints appeared aimed at trying to get the Army to adopt bigger caliber guns and ammo, something the service opposes.
According to defense officials close to the study, a group of assembled specialists on the matter, including both ballistics specialists and medical doctors familiar with bullet wounds, told the Army before it started the study that the problem is not the size of the bullet but the person pulling the trigger.
The specialists concluded that disabling an enemy combatant with an M-16 is more dependent on where a shot is placed, the number of hits that are placed on target, and the level of marksmanship training of the solider. The size of the bullet and its design are less important and the standard M855 ammunition, known as "green tip" ammo is fine.
The Army study concluded almost the same thing but failed to identify one fault of its own soldiers: They need more training to be better shots.
The study proved that the complaints from some units in Afghanistan were unwarranted. "There are some special operations units that never complained because they could shoot," one official told us. For those lacking marksmanship training, "they could shoot at someone 10 times but only hit him once or twice."
"The Army is very willing to spend a lot of money on guns and ammunition, but very little on marksmanship training," the official said.

On one side of the argument is ARL/SLAD/WMRD who historically have used the estimated kinetic energy (EKE) methodology (which is an assessment of ballistic gelatin using dynamic metrics (high speed photography - major dimensions of temporary wound cavity, striking yaw angle, and other metrics)) to assess wounding potential.

On the other side is ARDEC Picatinny, Navy, Marine Corps, FBI, combat surgeons, and others who support a static assessment of ballistic gelatin taking into account neck length (distance traveled before significant yaw), permanent cavity deformation, total depth of penetration, largest fragment recovered, and other metrics.

Most of the analysis and testing results indicate that shot placement far outweighs the minor terminal ballistic performance differences among the 5.56mm rounds and the M80 7.62mm rounds that were assessed. The range of performance is broad largely due to striking yaw angle, muzzle velocity, and other factors. Striking yaw is unique to the individual weapon as well as to the individual round for each shot.

Based on the testing/analysis conducted during this effort, none of the candidates tested possessed significant across-the-board performance factors that would warrant a switch from M855 as the standard issue, general purpose cartridge for Close Quarters Battle engagements. This conclusion may be less applicable to special operations units due to differences in training, weapon systems, tactics and operational tempo.

The Washington Times writers seem to have added their own conclusions. This line in particular stands out: "The Army study concluded almost the same thing but failed to identify one fault of its own soldiers: They need more training to be better shots." We didn't FAIL to identify that fault; we recognized that human nature in the heat of battle shrouded in the fog of war will always produce marginal "marksmanship." It is one of the reasons why the difference between rounds is negligible.

TC

 

[RON in PA]

Doesn't suprise me in the least and the same can probably be said for 9x19 ball. It's all about shot placement.

 

[cuervo]

All of the news outlets that have been reporting on this have very short memories.

Wasn't it just a few years ago how they were describing how these bullets would rip your arm off at the shoulder? How could they question the lethality of such a dangerous bullet that is so evil it shouldn't be allowed in civilian hands?

 

[Byron]

The lethality of the 5.56 was in the M193 round that was used in Nam.It was a 55 grain FMJ with a muzzle velocity of about 3240 FPS from a 20" barrel. It worked well. Byron

 

[Jim K]

There was a letter in the Washington Times on the 19th from one Art Bachman, who claims to have vast firearms expertise but who claims that the 5.56mm will cause only minor flesh wounds and equates it to a "22-caliber rifle" (presumably the .22 LR).

I replied (letter not published, at least yet) to the effect that while there have been valid questions about the combat effectiveness of the 5.56mm since its adoption in the 1960's, the reason for its use was that it allows controllable full auto fire from a light rifle, a more important consideration in combat today than a 3 mile range or the ability to penetrate thick trees.

There is something else interesting here. Many writers on the subject claim great expertise in guns, usually stating that they are hunters, gun dealers, former military members, shooters, etc. These claims are not easily verifiable; they rarely claim to be NRA members, something that could be easily checked.

IMHO, many of these writers are anti-gun liberals who have found a new issue on which to attack Bush and the war policy. They write on the subject, but have no real knowledge; their terminology often gives them away.

If questioned about the 5.56mm, I always make sure to say that it was adopted during the Kennedy administration, and has been used since. One person replied, "Oh. I though it was another Bush screwup." His agenda was obvious.

Jim

 

[Byron]

I was a 20 year old infantryman in Nam 68-69 and have great respect for the 16 and the M193. Byron D Co.,3/8th Inf,4th Inf Div

 

[Dobe]

Take a look here

http://www.thefiringline.com/forums/showthread.php?t=212937

 

['Card]

See, in this discussion, I think the problem is that they're asking the wrong question.

The point isn't whether or not the 5.56 round is adequate to neutralize a hostile combatant. Of course it is. A 7.62 round is also adequate, and for that matter, if your shooting is accurate enough, a .22LR is adequate too.

The question should be, which one is better?
Is the 5.56mm adequate? Sure.
Is the 7.62mm better? Yes.
Is the 9mm adequate? Yes.
Is the .45ACP better? Yes again.

They pretty much sidestep the entire "better" issue in the article, by saying that what differences there were weren't big enough to justify replacing the existing weapons. It's one thing to make that decision when you're a high-ranking officer looking at logistics and expenses for an entire Army. Ask an Infantryman about to wade into Indian Country the same question, and he may place a little bit more of a priority on "better".

 

[Byron]

Card,my experience with the M193 was that the bullet was devistating on contact more so than the 7.62.Granted our range was at the most 100 meters. My understanding is the m855 is not as lethal. Byron

 

['Card]

I'm a vet too, Byron - and my experience led me to different conclusions than yours - but that's what makes it fun to argue about. If we got 20 different combat vets into this discussion, we'd have at least 20 different opinions on the subject.

 

[Jeff White]

'Card said,

If we got 20 different combat vets into this discussion, we'd have at least 20 different opinions on the subject.

And we'd never settle anything. A quick search will bring up dozens of threads on this topic. They usually go well over 100 posts and get pretty acrimonious before they end up closed.

And of course we always get input from people who have zero experience but are willing to fight to the death (online) over an opinion based on what someone told them in a bar or at a gunshow, what they saw on TV or read in a book.

I always cringe everytime one of these threads gets started.

Jeff

 

[ryoushi]

I'm not a vet and I've never fired a shot at anybody in anger but I do have an observation. Most of the complaints I've seen latley also are accompanied by comparisons to 7.62 X 39mm with grunts being quoted touting the merits of any AK 47 they can scrounge.

I recently read We Were Soldiers Once And Young and in that story of the battle at the Ia Drang Valley and you have numerous accounts of US soldiers being hit with the deadly 7.62 x 39mm round and actually surviving and continuing to fight. I have a hunting buddy who tells of hitting a Viet Cong center mass with his M14 only to watch him get up and run off into the bush.

I hope we see a new rifle and bigger bullets for our troops soon but I don't think they are outgunned at all.

 

[Leatherneck]

I feel your pain, Jeff:

I always cringe everytime one of these threads gets started.

I thought it was useful that there is actually an attempt to quantify the data by people who make their careers developing weapons and projectiles for the Army and Marines.

Disclaimer: I'm a big-bullet guy myself. The Garand and the 1911 seemed to work out in WW II and Korea. They were used by kids arguably less-trained than our warfighters today.
Let the fights begin.

TC

 

[rangerruck]

readfing an article right now, that explains about how the bullet is supposed to act, and fragment, etc. in 5.56 It also explains about fps energy and kinetic energy or momientum energy. Now it seems that in the m4 types, the bullet can do its"thang" out to about 75 yards or so, penetriate and correct fragmentation. it keeps it's kinetic/momenutm energy out to about 150 yards or so. In either of these cases , if you get a good center mass type hit, either distance should be a kill type shot, unless the bullet just happens to miss everything. the kinetic energy for the bullets like 30/378 ,300 win , 300 rsaum, go all the way out to about 950 TO 1050 yards! OUCHY!

 

[Pickpocket]

It also wouldn't take very long to search out some stories where LE got into it with someone and the BG lived with two .45 slugs to the chest.

This is more a problem of expectations and "REEL vs. REAL" than it is of performance of the 5.56 round.
Some people still expect a person to get thrown against the wall upon getting shot, and when this doesn't happen....well....suddenly the 5.56 isn't "adequate".

The 5.56 round was chosen for light infantry because of its versatility, not because someone thought it was more effective than the 7.62 or some larger caliber. You can take precision shots out past 300m using iron sights...you can also make area hits on a man-sized target out past 500m. THAT's not going to happen with an AK, and it's even longer than some people can accurately shoot their scoped .308. The M16 - much like the HMMWV - may not be the "best in class", but it certainly is more versatile than any of the alternatives that people often suggest as replacements.

As for fragmentation, it doesn't happen 100% of the time. The round is really unpredictable in my uneducated, non-ballistic-studying mind. Someone smarter than me might dispute this, but that's been my experience. However, the round was designed to fragment at 2700fps. The modern 20" M16 sends its rounds at about 3200fps.
The M4 is actually where we hear more complaints, and that's because of its 14.5" barrel. The M4 using the standard NATO M855 dips below 2700fps somewhere well below 100m. That means that the projectile is less likely to fragment. We got a lot of complaints following Mogadishu about this very same thing.

At the end of the day - there may be better rounds out there - but the 5.56 does what it's supposed to do...and that's put holes in people.

Oh - and "better" is a relative term.

 

[Surat]

Been lurking for a while now, but this is my first post.

On the matter of lethality. . I used to hear the same sort of jibes about me carrying a pocket .380 off duty in summer months (hides alot better in shorts then a Glock 22) from guys in my department. "Oh all that's gonna do is p!ss them off. . ." to which I'd reply, "ok, fine, lemme go out to the truck, find a 3/8 inch drill bit, slap it into my craftsman and drill it into your chest three or four times". . . they usually shut the &*^$ up after that.

Always and never are two things that don't apply to humans. There is no such thing as a magic "kill all" bullet. When I was stationed at Bragg two women were abducted and murdered at the Army camp ground. A third was abducted, shot three times in the stomach, and left for dead at the campground next to the Army Airfield. She crawled all the way to Merch. Blvd and flagged down a motorist for aid and lived.

. . .lotsa things can ahppen in a firefight. Lotsa things happen in a trauma situation. People that you think will live from a wound curl up and die. People that you think "no fing way" live. We had a guy that used to come to jail here regularly that survived being shot, stabbed beaten near to death, and lit on fire. A long time alcoholic, ne at one time WALKED into the jail with a .52 BAC. For the rest of us that's DEAD. He died this year choking on a sandwich.

If given the choice between a Garand, an AK, and a M-4, I'd take the M-4. Not becasue I especially like an M-4* or dislike the others. It's just that if going into combat there's no such thing as too much ammo, and I know that I can hump alot more 5.56 then .30-06 or 7.62x39.

M-4 has a 14.5" bbl. Effective range is 250m as opposed to 300m for the 20" bbl A2

Had to cork off with this. . now back to the shadows.

(*note: I've never liked the gas system in the AR, however. . . the H&K 416 is really interesting to me. . . I'd love to get one of them one day. . . guess I need to start doing pushups and get on the SERT team.)

http://www.hkdefense.us/corporate/media/pdf/416revised4-5-05.pdf

 

[Surat]

double post, oops

 

[Pickpocket]

Thanks for the catch on the barrel length, Surat; Edited to reflect. Don't know what I was thinking when I typed that...

 

[Dave Rishar]

A more enlightening comparison might be made between the terminal effects of the M4 and those of 5.56mm weapons with longer barrels.

It's the same old story: the cartridge was designed for a lighter bullet, a considerably longer barrel, and a slower twist rate. Everything has been altered in such a way to reduce effectiveness and people are wondering why it no longer works as advertised? I'm wondering how it works at all. Perhaps that whizbang 5.56mm isn't as bad as we thought.

Another question: if the service rifle was exchanged with one in 7.62mm that still used a 14.5" barrel, would the results be more satisfactory, keeping in mind that ammunition load would be reduced, accurate burst fire would be pretty much impossible, and any use indoors would be decidedly unpleasant? Comparing a battle rifle with a 20+" barrel to a carbine with a 14.5" barrel is not particularly informative, nor is it entirely fair. I don't believe that the problem here is the cartridge.

 

[Jim K]

The M16 and the 5.56mm ammo was chosen because its lethality is adequate for modern tactics, and the combination allows controllable full auto fire from a light rifle. The M14 is useless in the FA mode (yes, I have fired them that way), and the M1 is a good, big, heavy rifle, with the emphasis on big and heavy.

The FAL is not much better in FA fire and most users restricted them to semi-auto as was done with the M14.

For modern tactical doctrine, the FA capability was seen as outweighing the need for bullets that will shoot through foot-thick trees and have a three mile range.

Surgeons in VN reported that they could not tell the difference among wounds from the M14, M16 and AK.

Jim

 

[Cpl Punishment]

Within its fragmentation range, the 5.56mm is extremely lethal. Damage to flesh within this range is often worse than with non-fragmenting 7.62mm FMJ. Outside the fragmentation range, there is much less tissue damage, and shot placement becomes much more critical. FWIW< I hear our men are shooting quite well, dropping the enemy with somewhat regularity at 400+ meters, and certainly closer than that.

There's been soem statements made about the range at which that fragmentation can occur, from actual data, the reliable fragmentation threshold is approximately 2700 fps for M193 and M855, this velocity occurs at roughly:

20" barrel, M193: 190-200 meters
14.5" barrel, M193: 95-100 meters
20" barrel, M855: 140-150 meters
14.5" barrel, M855: 45-50 meters

You lose a LOT when you drop to an M4 length barrel.
But the fact remains, fragmentation or no, a good hit will get the job done.

 

[shooter94]

Has anybody mentioned the M-16, was intended as an Military law enforcement weapon? Mainly for the Airforce?...

It's lethality with M193 is the twist ratio...1 in 12 inches. Just enough for accuracy, but with a slight wobble and yaw...hence your lethality.

If we're going to keep the system, I'd suggest going back to the original twist ratio.

 

[Warbow]

It's lethality with M193 is the twist ratio...1 in 12 inches. Just enough for accuracy, but with a slight wobble and yaw...hence your lethality.

If we're going to keep the system, I'd suggest going back to the original twist ratio.

From here:

The importance of rate of twist in wounding is a frequent subject of what we politely call "ballistic myth." Any projectile that has a "center of pressure" forward of the center of gravity will tend to tumble.

[...]

At 3200 fps M193 is typically spun up to more like 256,000 (1:9" twist) to 330,000 rpm (1:7") so that Sg approaches 1.9 or 2.0. 1:12" rifles will spin rounds at around 192,000 rpm and 1:14" rifles around 165,000 rpm. You can see why 1:14" rifles might have had trouble stabilizing M193 rounds.

Clever math types will see that density of the medium traversed (air in this case) has a dramatic effect on the spin required to maintain the Sg (density being in the first term's divisor). This is why cold conditions tend to dip "barely stable" rounds below the stability threshold. Without doing too much calculus it will be seen that an increase of three orders of magnitude (1000) in this variable will be a dramatic one for spin requirements. To balance things spin must be increased to compensate.

Through human flesh (which varies from 980 - 1100 kg/m^3 or about 1000 times the density of air) something on the order of 95,000,000 - 100,000,000 rpm is required to stabilize a projectile at speed. Given these differences it will be seen that the difference between a 1:12 or 1:14" twist when it hits flesh and a projectile launched from a 1:9 or 1:7" weapon is so small as to be beyond measuring.

 

[Dr. Dickie]

It's funny, the way I read the article, I came to exact opposite conclusion:

"The specialists concluded that disabling an enemy combatant with an M-16 is more dependent on where a shot is placed, the number of hits that are placed on target, and the level of marksmanship training of the solider."

That says that the M16 is more dependent on number or hits and round placement, more dependent than what? The 7.62 NATO round. So you need less hits and you do not need to be as precise with your hits with the M14. I conclude from that, I would rather have the M 14--course, weight and number of rounds carried also has to be concidered and the article did not get into that (this should be a wash as a modern 7.62 weapon can be made lighter and you would not need to carry as many rounds since you are not firing rapid fire).
Having the ability to control the weapon during rapid fire (which you could NOT do with the M 14) is a big plus, but only if you can aim it well. The real issue (to me) is, is having the ability to shoot in rapid fire (other than the SAW) needed, or is "punch" needed. If the squad needs every man able to lay down suppressing fire, then the M 16 is better. If the squad needs kill capabilities rather than suppressing fire, then the M14 might be better (weight and other issues need to be considered).
But, hey I am no expert, just a gun nut.

 

[gopguy]

Actually a discussion of the merits and demerits of the 5.56 round took place a few weeks back. I think the posting of the info here is what everyone is looking for.

http://www.ammo-oracle.com/body.htm#twistduh