5.56 AR stopping power (and the x39 and 5.45 competition)

[d2wing]

The idea that there was a accepted doctrine that the 7.62x 39 was more lethal than the 5.56 was only true among the ignorant and internet experts that know next to nothing. AK fanboys and such and the poor souls fooled by Fackler.

 

[JShirley]

That is not exactly how it works. One of Facklers mistakes. You can believe whatever you want. That doesn't make it true. Over the years I have explained how it does work. It doesn't seem to matter. So think what you want.
The primary reason 5.56 wounds are larger and more destructive to flesh is the high velocity. Flesh, like water, can only yield to objects at a certain rate until resistance causes the flesh to transfer energy more like a solid beyond the wound channel. Similar in principle to a boat achieving enough speed to go up on plane. Where the water no longer can flow around the boat so the boat rides on the surface rather than displace the water I hope that helps. Fragmentation occurs as a result of that resistance but that is incidental rather than the wounding mechanism.

Energy is energy. The 5.56x45mm at closer distances, has less. Energy is used to turn a bullet into penetration, expansion, and fragmentation. Now, you claim that pushing pieces of metal through living tissue "is incidental rather than the wounding mechanism". I'm pretty sure putting a broadhead arrow through a deer's lungs transmits almost no pressure wave, yet that deer will be deader than Elvis.

I'm going to agree that rapidly transmitting shock to the body is destructive, but disagree that your newfangled .250-3000 is a death ray, and can be used on any game, no matter how large, because it's so destructive.

Yes, a high velocity round has been around for over 100 years. The US government didn't adopt it as its primary rifle round. It doesn't do a good job on game larger than deer- why? Because your magic pressure wave is just one part of the effectiveness formula, not the "(primary) wounding mechanism".

Sure, speed does kill. But only when intelligently combined with the wounding mechanisms of penetration, expansion, and fragmentation, to go with that shock.

John

 

[JShirley]

The idea that there was a accepted doctrine that the 7.62x 39 was more lethal than the 5.56 was only true among the ignorant and internet experts that know next to nothing. AK fanboys and such and the poor souls fooled by Fackler.

The 7.62x39mm, at closer ranges, is potentially more lethal, with the right bullet. It definitely isn't more lethal with 57-N-231S or 57-N-231SL (than M193 from 20" barrels), in most circumstances.

 

[Double Naught Spy]

Correct me if I am wrong, as I certainly am human, but I was under the impression that a big reason the 5.56 was originally chosen was it’s ability to seriously wound and not outright kill an enemy soldier. The rationale being that wounded men takes others to carry, treat, rehabilitate, etc. therefore adding to logistical headaches and sapping enemy numbers and morale. A dead man is just that, DRT. (Dead Right There)

Many of you far more knowledgeable will hopefully set me straight on this if I am off base.

Stay safe.

That is a myth, no doubt promoted by the military sort of like the claims that you can't legally shoot .50 BMG at people, only materials, also promoted by the military and also untrue. No, it was not chosen because it will wound more than kill. However, the military had trouble selling the rifle to many soldiers because of real or perceived ineffectiveness during Vietnam.

The theory of taking out more than one soldier with a wounding shot works great, if the enemy cares about its people. Not all our enemies do. We nearly always do. We will get 20 guys injured or killed and various vehicles or aircraft destroyed saving one wounded person, so the theory works really well on us.

 

[12Bravo20]

The M855 NATO round will actually do better with a 1-9 twist barrel while it is too long to properly stabilize in a 1-12 twist barrel (M16A1). The reason that the M16A2 and M4 have a 1-7 twist is so that the longer M856 tracer round (63.7 grains) will properly stabilize. The M856 was found to be very inaccurate in a 1-9 twist barrel.

My experiences echo others. The M855 does just fine when a center mass or head shot is made. The only time that has not been 100% true is a center mass shot on someone that is hopped up on drugs.

I have never hunted animals with 5.56/223 ammo so can't comment on that. I have used 5.56 in combat a few times when not carrying the M60.

 

[d2wing]

Energy is energy. The 5.56x45mm at closer distances, has less. Energy is used to turn a bullet into penetration, expansion, and fragmentation. Now, you claim that pushing pieces of metal through living tissue "is incidental rather than the wounding mechanism". I'm pretty sure putting a broadhead arrow through a deer's lungs transmits almost no pressure wave, yet that deer will be deader than Elvis.

I'm going to agree that rapidly transmitting shock to the body is destructive, but disagree that your newfangled .250-3000 is a death ray, and can be used on any game, no matter how large, because it's so destructive.

Yes, a high velocity round has been around for over 100 years. The US government didn't adopt it as its primary rifle round. It doesn't do a good job on game larger than deer- why? Because your magic pressure wave is just one part of the effectiveness formula, not the "(primary) wounding mechanism".

Sure, speed does kill. But only when intelligently combined with the wounding mechanisms of penetration, expansion, and fragmentation, to go with that shock.

John

Here comes the pitchforks and torches. And misquotes. As expected.

 

[JShirley]

Here comes the pitchforks and torches. And misquotes. As expected.

Yeah, you seem so persecuted. Again, energy is energy. 7.62x39mm has more of it at closer ranges. This means it is potentially more destructive, with the right ammo.

The idea that very fast rifle rounds cause more damage is not a new idea. Some folks have nursed this belief since the .30 WCF, then the .250-3000. And for mass, it's true: a lighter bullet going much faster can do as much damage- or, close enough to it- to replace a much heavier, slower bullet. So we've seen a trend away from large bore, slow cartridges to smaller bore, faster ones. But a difference of 600 fps doesn't magically do an immense amount more damage, when both bullets are already traveling over 2000 fps. The damage demonstrated by M193 bullets vs the issued COMBLOCK 57-N-231 in Vietnam was due to bullet construction. There is some M193 built by NATO allies with thicker jackets which doesn't demonstrate the wounding potential of US-made M193, despite being the same velocity.

To quote a member, "You can believe whatever you want. That doesn't make it true."

 

[JShirley]

Recall, too, that, if there is a need to spoil the bad guy's day at 1000m, there are plenty of tools for that (60mm mortars at the Platoon level for one). Get artillery assets in play and you can rain ruin 5 & 10 KM away. Get aviation assets, and you can reach even further.

Weight matters in combat. Every pound of ammo you don't have to bring is a pound of food, or fuel, or some other similar thing necessary to keep riflemen up by the FEB/MLR.

In early 2007, my gun team hit an enemy gun that had been set up about 2200 away*, overlooking our FOB. It was a 120mm we used- why bother with our 81mm or 60mms?


*A sheer stroke of luck, 1 in 50,000 shot, a first round hit after shifting onto that target.

 

[jmorris]

Energy is energy…
Energy is used to turn a bullet into penetration, expansion, and fragmentation.

I don’t think one can make such a statement in light of the facts.

If it were simply “energy is energy” world we wouldn’t need more than one kind of bullet construction, in any caliber at any speed.

We know that different styles of bullet construction change the amount of penetration, expansion, and fragmentation, one gets. Not necessarily the energy contained in the projectile.

 

[JShirley]

I don’t think one can make such a statement in light of the facts.

If it were simply “energy is energy” world we wouldn’t need more than one kind of bullet construction, in any caliber at any speed.

Missing the "intelligently combined with the wounding mechanisms of penetration, expansion, and fragmentation" part of what I wrote. Yes, bullets of dramatically differing weights, fired at dramatically different velocities, will behave in dramatically different ways

 

[jmorris]

Yes, bullets of dramatically differing weights, fired at dramatically different velocities, will behave in dramatically different ways

Even bullets of the same weight AND velocity’s can behave in dramatically different ways, based upon construction.

 

[CapnMac]

And, there remains a significant difference between what one man with a rifle coping with one critter, rodent, antelope, deer, what have you; and that person is one of nine, of thirty, of 150, of 700 to 900 all told, who faces some similar number.

 

[d2wing]

Yeah, you seem so persecuted. Again, energy is energy. 7.62x39mm has more of it at closer ranges. This means it is potentially more destructive, with the right ammo.

The idea that very fast rifle rounds cause more damage is not a new idea. Some folks have nursed this belief since the .30 WCF, then the .250-3000. And for mass, it's true: a lighter bullet going much faster can do as much damage- or, close enough to it- to replace a much heavier, slower bullet. So we've seen a trend away from large bore, slow cartridges to smaller bore, faster ones. But a difference of 600 fps doesn't magically do an immense amount more damage, when both bullets are already traveling over 2000 fps. The damage demonstrated by M193 bullets vs the issued COMBLOCK 57-N-231 in Vietnam was due to bullet construction. There is some M193 built by NATO allies with thicker jackets which doesn't demonstrate the wounding potential of US-made M193, despite being the same velocity.

To quote a member, "You can believe whatever you want. That doesn't make it true."

At least you quoted me correctly once. In the past I have posted pages about this. Believe what you want because this is America and truth doesn't matter. My career was in part was catching crooks, liars, idiots. Now they let them go. But one day truth will come.

 

[Shawn Dodson]

Let’s have a discussion on what’s (most) effective. I feel like it used to be dogma in earlier decades that 7.62x39, despite being Commie, was “best” because it’s a hard hitting .30 caliber, albeit one with limited range compared to .308. But the USSR switched to 5.45x39, evidently happily enough, and we’ve all heard the stories of the “poison bullet,” where these rounds were used to deadly effect in Afghanistan by the Soviet military. The 7N6 round apparently has a hollow cavity near the nose that causes the bullet to deform upon impact, making for a yawing wound channel and more damage than a 5.45mm bullet might otherwise cause.

5.45x39 produces substantially less wound trauma than M193, M855 and M855A1.

5.45x39 yaws but doesn't fragment. The reason why it earned the nickname "poison bullet" is because those who were wounded by it usually died because infection set in instead of tissue damage.

 

[Shawn Dodson]

Sadly Fackler has mislead a generation or more of shooters. He claims of wounding mechanisms are in noway scientific or accurate. He never had any training in ballistics or how bullets work. He made up most of what he said. He was a coroner and part of a group bent on discrediting the AR.
Anyone with experience knows that the Army was correct in the research that a high velocity round like the 5.56 is far more lethal than the 7.62x 39.

 

[Shawn Dodson]

That is not exactly how it works. One of Facklers mistakes. You can believe whatever you want. That doesn't make it true. Over the years I have explained how it does work. It doesn't seem to matter. So think what you want.
The primary reason 5.56 wounds are larger and more destructive to flesh is the high velocity. Flesh, like water, can only yield to objects at a certain rate until resistance causes the flesh to transfer energy more like a solid beyond the wound channel. Similar in principle to a boat achieving enough speed to go up on plane. Where the water no longer can flow around the boat so the boat rides on the surface rather than displace the water I hope that helps. Fragmentation occurs as a result of that resistance but that is incidental rather than the wounding mechanism.

M193 and M855 yaw and fragment. At velocities below 2700 fps the bullets don't fragment substantially and both bullets produce less wound trauma. The less fragmentation, the less wound trauma produced.

The fragments pepper soft tissues with holes, which are then torn open by the subsequent temporary cavity. The temporary cavity works in synergy with fragmentation to increase the amount of permanent tissue disruption.

7.62x39 and 5.45x39 also yaw, but they don't fragment. When they yaw they produce a temporary cavity about the same diameter as M193 and M855, but the AK rounds don't damage as much tissue.

 

[denton]

the part about FMJ is not necessarily true. It is illegal to hunt with non-expanding rounds in some states. This is despite the fact that something like a cast lead load from a large bore handgun or rifle is extremely effective on game. So, the fact that something is legal or not legal can't be taken as automatic guarantee that something will or won't work against a human attacker or target.

Small point of order....

As you said, many states, including mine, prohibit hunting with non-expanding bullets. Once upon a time, I thought that I wanted to hunt with cast lead, so I checked with our fish and game folks. Turns out, in this state, cast lead bullets are considered to be expanding.

 

[JShirley]

Even bullets of the same weight AND velocity’s can behave in dramatically different ways, based upon construction.

Yes, the bullet design would be the "intelligent" part I mentioned. Let me give you an example.

I want my deer hunting ammunition in most calibers* to expand at least somewhat, and penetrate deeply enough to penetrate vital organs, and hopefully provide an exit hole for additional quick blood loss. There is a 125 grain .308 HP that provides dramatic fragmentation at .30-06 and .308 velocities. It's a varmint bullet. I use this same bullet in my .300 BO for deer. Why?

At 7.62x39mm/.300 BO velocities, this bullet expands and penetrates. I don't need a .308 varmint bullet, but I do need a .300 deer round. And I know the effects of velocity on this round, and can use it appropriately.

*I have some .45 Colt cast lead loads that are the exception.

 

[upptick]

...A 5.56 AR-15 and a 7mm Remington mag, or .30-06 would be all the rifle that anyone in the US needed, until you get up to the big bears or moose....

Of course, the 6.5 Swede has likely taken more moose than any other round and the 6.5 Creed is arguably just a slightly improved 6.5 Swede....

 

[JShirley]

Of course, the 6.5 Swede has likely taken more moose than any other round and the 6.5 Creed is arguably just a slightly improved 6.5 Swede....

6.5x55mm did also come to my mind. The Creedmore is only "improved" in the way the .308 is an "improvement" over the .30-06. In both cases, the older cartridge can throw a heavier bullet with lower pressure. For most uses, 6.5 Creed or .308 performance will be practically as good, but at the extremes, the difference can be seen. (Being newer, and specifically designed for accuracy, I'll agree the CM is probably an improvement in that arena.)

John

 

[Carl N. Brown]

"Eugene Stoner demonstated 556 to General Lemay ...."

The story I have heard over the years about the head of the Strategic Air Command picking the 5.56mmm AR.
Air Force was using M1 Carbines for flight line protection, powerful enough to stop a saboteur but not so powerful as to do great damage to parked aircraft.
The M1 Carbines, WWII war babies, were getting old.
At the time the Army was talking about replacing M1 Carbine, M1 Garand, M3 SMG with the M14.
To Lemay, the replacement for the M1 Carbine had to be powerful enough to stop a saboteur but not so powerful as to do great damage to parked aircraft.
Lemay thought the Armalite Rifle in 5.56 met airfield security requirements much better than the 7.62x51 M14.

 

[CapnMac]

Lemay thought the Armalite Rifle in 5.56 met airfield security requirements much better than the 7.62x51 M14.

Lemay was also well aware of the issues in getting people who had qualified on 5# Carbines to achieve the same qualification on 11# M-14 rifles.

 

[Goosey]

The idea that there was a accepted doctrine that the 7.62x 39 was more lethal than the 5.56 was only true among the ignorant and internet experts that know next to nothing. AK fanboys and such and the poor souls fooled by Fackler.

He actually reported the opposite about 5.56 vs 7.62x39 FMJ. But he seemed to share a similar opinion to Jeff Cooper on the .223 in general.

 

[JShirley]

I definitely don't belong to the 5.56 haters' club, but denying that "battle rifles"- 7x57, 7.62x51, 7.62x54, .303, etc- are more powerful, and therefore, potentially more destructive, would be denying physics and logic.

John

 

[Mosin77]

Thank you gentlemen for your very instructive commentary, especially those who have first hand experience.