Terminal effects of AK vs AR perspective

[Slamfire]

On of these days I am going to write in detail my outrage about how a bunch of gun writers made a wildcat round that became the service round of the United States. You can read the three page history in the 1971 Guns and Ammo Annual.

Robert Hutton, Technical editor for Guns and Ammo Magazine is apparently the “developer” of the round. His criteria was a muzzle velocity, as measured from a bolt rifle, of 3300 fps, with a 55 grain bullet. This velocity was calculated as what was need to keep the bullet supersonic at 500 yards. (Why that was important, I don't know) Chamber pressure was calculated, using a slide rule, at 55,000 psia. He wildcatted a 222 Remington round, and the only lethality tests were penetration tests on US Army helmets at 500 yards.

It will take much work to outline what a ridiculously inadequate development program this was, and it will take work to write about the known problems these Confident Idiots created, but it does not take too much research to find about the good American boys who died because of the failures of the cartridge, and the rifle. However, I will outline a few objections: The round was developed to be a high pressure round from the start and its pressure has only risen in time. Pressure is not anyone’s friend and if you can do the same job at lower pressure, you will likely have less functional and mechanical problems. The case drags on extraction, which causes the round to fall off the bolt face. It sort of works with brass, but steel case ammunition is unreliable. The rim is too thin, pulls off easily. Like I said, I am going to work on this in my leisure, but it is amazing a couple of Gun writers can whip up some half baked round, and get the thing adopted as a service round. The problems we have had since the type classification are all the result of this round not being the best of the best, but simply what a Gun writer whipped up based on his level of incompetence, a bench rest rifle, a couple of dies, commercial bullets, and paper slide rules.

The only lethality testing was against helmets, so that is your performance baseline. The military 223 will poke holes in sheet metal at 500 yards. If that level of lethality is inadequate, well, too bad. What the heck did you expect from a commercial, off the shelf round?

As for the Russian round, it has proven to function fine in all the world’s environments, and with cheap steel as a case material. As for lethality criteria, we will never know unless the post WW2 Russian documents make it on Wikileaks. The Russians wanted an intermediate round, we don’t know how they came up with the numbers, that is bullet weight, bullet diameter, and velocity, but you can bet they were looking for the round which provided a minimal acceptable lethality. They had the 7.62 X 54R round in service, which pushes a much heavier bullet faster, it is in the 30-06 class of rounds. I am certain the Russians would have loved to keep the lethality of the 7.62 Mosin round, but they did not want the blast, recoil, weight, and length of the thing. From numbers that I have seen, the 7.62 X 39 is around a 30-30 in terms of lethality.

I am certain that the Russians considered hitting someone at 300 yards, poking a hole in them, maybe through winter clothing, adequate enough for a combat round. I think they signed the Geneva Convention, so expanding bullets were a no-no. The basis of the Geneva Convention was that putting a small hole in a solider was enough, and something that artificially caused massive trauma was inhumane. If you don’t like that, get the Geneva Convention changed.

[kraigwy]

And then, the Russians took a look at our 223/5.56 and dumped the 7.62X39 for the 5.54X39.

Just say'n

[Jimro]

You can estimate lethality by Accuracy, Penetration, and total volume of tissue disruption.

First up: Accuracy

The M4/M16/AR15 can routinely place accurate point fire on targets 600 yards away. The AK47 cannot, the sights are maxed out at 300 meters. The AR/M4/M16 platform easily accepts optical sighting solutions, has easy to use ergonomics, and is capable of easy head shots in the distances given, even using a battlesight zero designed for 200 meters. The AK platform has rudimentary sights, and the rifle must be modified to accept an optical sighting solution, and has never been noted for accuracy.

Winner AR/M4/M16 and the 5.56x45.

Second up: Penetration

The standard weight of a 5.56x45 projectile is 62gr, only one grain shy of the 123gr 7.62x39 standard pill. The 5.56 bullets have a higher initial velocity, but much less mass, and the mild steel jacket for the 7.62 round ensures that it will hold together even through tough, dense mediums. The M193 55gr round was upgraded to the 62gr SS109/M855 because of penetration on steel helmets, and then upgraded again to the Mk318 and M855A1 due to barrier penetration concerns. The 7.62x39 loading never needed to be upgraded.

Winner, 7.62x39 and the AK/SKS

Third up: Disruption

From the muzzle to infinity, a 123gr FMJ from a 7.62x39 will never fragment in a human body. The mild steel jacket and low velocities ensure that the bullet will go through just fine unless it is scored into a "dum dum" round which will cause bullet disintegration in human tissues (I've seen the wound pics from a brush war in Africa, was a dime size hole in the front, softball size in the back).

From muzzle to about 90 yards, every bullet ever used from an M16 or M4 as a standard issue rifle round; M193, M855, Mk318 Mod0, and M855A1, has a very high likelihood of massively disrupting in soft human tissue. The M855 green tip is "yaw dependent" so that not every bullet will fragment, but all the rest have very predictable performance.

So, for disruption at close range the winner is 5.56x45, and beyond close range the larger diameter of the 7.62x39 will create a larger permanent wound cavity. However, since the 7.62x39 has an accuracy penalty at longer ranges, the 5.56x45 is the winner of this category as well, specifically since the M855A1 and Mk318 have longer ranges where bullet disruption leads to increased tissue disruption.

So there you have it, my assessment. The 5.56x45 wins the Accuracy and Disruption departments, the 7.62x39 wins in Penetration. That seems like the 5.56x45 would be the better choice for combat situations not involving shooting through cinder block walls to get to bad guys.

Jimro

[stagpanther]

So there you have it, my assessment. The 5.56x45 wins the Accuracy and Disruption departments, the 7.62x39 wins in Penetration. That seems like the 5.56x45 would be the better choice for combat situations not involving shooting through cinder block walls to get to bad guys.

Until a better bullet comes along maybe, but my guess lots of people have tried. I may try some of barnes' tac tx bullets made for the 300 BO on my new AK and see what happens just for kicks.

[Jimro]

There's a LOT of things that can change that assessment. If someone wanted to used cast bullets, there's no way I'd recommend the 5.56x45 over the 7.62x39 for that.

Or even if you start using civilian hunting bullets in 7.62x39 out of an AR platform? Yeah, now you've got a pretty darn good compromise on accuracy, penetration, and disruption across a wide range of tactical scenarios.

I tried to keep it to the military standard stuff that I know because that is pretty concrete and seemed to be what the OP was looking to compare.

Jimro

[Slamfire]

First up: Accuracy

The M4/M16/AR15 can routinely place accurate point fire on targets 600 yards away. The AK47 cannot, the sights are maxed out at 300 meters. The AR/M4/M16 platform easily accepts optical sighting solutions, has easy to use ergonomics, and is capable of easy head shots in the distances given, even using a battlesight zero designed for 200 meters. The AK platform has rudimentary sights, and the rifle must be modified to accept an optical sighting solution, and has never been noted for accuracy.

If long range precision was desired by the US Army, Soldiers would be issued M14's and 7.62 Nato rounds. Instead the Army walked away from precision long range shooting in 1964. The Soviets walked away some time after WW2 it took the Americans longer. I recall reading in a number of places where the Army stated the effective range of the M16 was 300 yards. The original M16's, the elevation was adjusted by rotating the front sight post, the rifle was sighted in and no one expected anyone to be adjusting the elevation for 500, 600 yard shots.

Whatever expectations you might have about precision long range shooting, Big Army is not in agreement with you.

I have never pulled targets for a shooter using an M4 type weapon. But I can say with a standard 20 inch barrel, the 223 round is running out of gas at 600 yards. It is below super sconic, You can't feel the impact, you have to see the bullet hole to know that it hit paper. The AMU got the rules changed so they could call the AR10 a service rifle. They were being out shot by civilians with Garands and M1a's at 1000 yards, so, they got a rule change and dumped the 223 for 1000 yard shooting.

[kraigwy]

I'm reading soooo much that isn't true here.

The Effective range of the M193 ball out of the M16A1 was 460 meters.

I've pulled the pits at 1000 when the M16 Service rifle were used and the 223/5.56 still cracked over my head because they were super sonic.

The NRA did start using the AR10 style rifles in Service Rifle categories, the CMP doesn't
Then again, the NRA Service Rifles "aren't). They resemble nothing of the arms room service rifles out side of outward appearance (some times). A good example is my Heavy Match M1A doesn't look anything like the M14s I used in Basic.

The ARs in 223/5.56 dominate the High Power Matches.

PENITRATION:

Small fast bullets will out penetrate the slow heavy bullets, even in FMJ.

Below I did a little test on penetration. Using a 7.62X39 FMJ, a M193 55 gr. 5.56, and 204 Ruger. The Ruger came in first, the 7.62X39 came in last.



Had a match on steel targets at our club. One guy was using an M4 style rifle and 77 gr SMKs. For some reason he penetrated our targets, no one else did. Looking at the steel I notice the holes appeared to be burned through as if a torch was used.

I re-visited Weeks "Men Against Tanks" and read that when tanks first came out, soldiers would pull the bullets out of their cases, re-insert them backwards, and they would penetrate the armor of thin skinned WWI tanks. What occurred the lead core was so hot it would melt through the armor much like a Shape Charge, setting the tanks fuel and ammo on fire.

Current wars have taught us that we do need extended range systems and create Designated Marksman to engage targets beyond those engaged by the average soldier.

The Army took M14s out of Mothball, took back the M14s loaned to civilian clubs, for the DM rifles. But there weren't enough, so the AMU with the CMP started a DM program training DM shooters to use M16s with 77 gr. SMK ammo. It worked and is effective.

(you can buy a DVD on training Designated Marksman from the CMP for $6.95).

There is a big difference in the service rifles you see at NRA matches and the Arms rooms of our military.

You want "as issued" matches you have to look toward the CMP's Modern Military Category in their GSM matches. The ARs dominate those matches. (match rifles are not eligible to be used).

What you don't see often or at all is the AK/SKSs being used. I've seen a couple show up at the CMP matches I run, but never saw one twice.

Don't see many at 3-gun matches either (which are relatively short range matches.

The army determined a long time ago that 60 ft lbs of energy is required to produce a disabling wound. The Average 7.62X39 should do that at 2500 yards. The M193 Ball only about 1300, The M855, 1850 yards, the 77 SMK 2550 yards.

So the weakest link is not distance but accuracy. Accuracy does matter in small arms used in the military.

[stagpanther]

Just got back from firing the first 14 cartridges through my brand-spankin-new PSAK gen 2 and took a couple of interesting pictures. The place I shoot had some solid concrete road barriers discarded--so I figured--why not?



The bullet below was recovered from the right-most divot which is about 2" deep. It's a 123 gr federal fusion. If you look closely--you can see what I believe is the front meplat of the bullet still relatively intact at the center.

[noonesshowmonkey]

Originally Posted by kraigwy

I'm reading soooo much that isn't true here.

As usual. Internet gun forums are dank, nasty caves where mushrooms grow thick on all of the bull-CENSORED--CENSORED--CENSORED--CENSORED-.

The information is out there. Folks just suffer from profound confirmation bias, and disregard data points that don't agree with their version of the truth.

Most 7.62x39 rounds do not frange / disintegrate on impact, due to the low velocity and the bullet design. 8m3, Hornady TAP, etc., definitely do, but those are the exception, not the rule.

Damn near any 5.56x45mm at SAAMI NATO pressures will fragment at a given range, often farther than people think, due to the high velocity. The exceptions are 855, 855A1, etc. with steel penetrators.

A common theme between the two above statements is that bullet design plays a massive role in how a given projectile performs at the business end of it's trajectory. You can't change physics, however, and velocity is king.

Past that, as you pointed out, accuracy of the individual shooter is a far more deciding factor in how a round performs than the round itself. No round performs well on a miss (except ordinance).

[stagpanther]

BTW--I wasn't trying to start a "one is better than the other" firefight--though I guess that's exactly what happened. My personal opinion is formed mostly based on what a friend who is a sniper and did multiple combat tours told me--he said no way he'd take an AK over an M4. Doesn't mean I can't have fun shooting both though.

[noonesshowmonkey]

Originally Posted by stagpanther

Doesn't mean I can't have fun shooting both though.

And that is chief among my rubs in this conversation. Shooting people is never for funzies. For those of us that have to consider that question, we are concerned specifically with raw data and cold reality, and we don't really care what dog you have in this fight, or your opinion, unless that dog is your own life.

I'm not tying to call you, specifically, out when I say this.

[Bartholomew Roberts]

Small fast bullets will out penetrate the slow heavy bullets, even in FMJ.

It depends on the medium. 5.56x45 will outpenetrate 7.62x39 in steel because of velocity; but shoot the rounds into ballistic gel side by side and 7.62x39 usually outpenetrates because the 5.56mm M193 bullet is lighter, decelerates faster/yaws first, and then breaks apart. If you use a bullet that doesn't break up (like say a 55gr TSX), it is a closer contest but the 5.56mm usually slows down faster because a lighter projectile sheds energy faster.

Which is one of the points the original article addressed that you rarely see discussed regarding 5.56 terminal ballistics.