Here is the promised penetrator from a delinked round of Israeli M855 with 62 grain SS109 projectile. Note the nearly complete lack of deformation (the leading edge has very slight rippling) despite coming apart inside a solid piece of wet oak.

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If it had been a .223 round (either "practice" or "duty") fired out of an AR-15 instead of a 5.56, how much different would the resulting wound have been?

quote:

Originally posted by snoris:
If it had been a .223 round (either "practice" or "duty") fired out of an AR-15 instead of a 5.56, how much different would the resulting wound have been?

A simple question, but despite its validity, it’s one that doesn’t seem to have any clear and simple answers.

The first issue is what do we mean by “practice” or “duty”? The specifics of the load of a cartridge like the 223 Remington make significant differences in their wounding effects. That much we can be certain of. For example, there is an illustration of how a military bullet is yawing as it strikes a gelatin block, and the difference that high yaw versus low yaw makes in its effects. A bullet that hits with its nose aligned with the direction of travel takes longer to start tumbling and delivering more of its energy than a bullet that strikes with its nose more diverged from its direction of travel.

So, if the orientation of a bullet when it hits the target makes a difference in wounding potential, what about all the others: weight, velocity, construction are the main variables.

Some bullets like the Speer 62/64 grain Gold Dot penetrate deeply even through barrier materials and are the type most hunters would like if using the 223 for hunting something like deer. On the other hand, there are several heavy (75-77 grain) open tip bullets used in the cartridge that (evidently) tumble and fragment reliably upon striking fleshy targets. They deliver their energy quickly with less likelihood of penetrating deeply before doing so and avoid the reported problems with some hits with military bullets. Because of considerations like those, I chose Gold Dot loads for my agency’s duty weapons that might have to be used against barriers, and Hornady 75 grain open tip bullets for personal short range defense.

As for your question about practice versus standard military loads, with full metal jacket bullets velocity is the primary cause of their (usual/occasional?) massive wounding effects. In my own limited testing of two similar loads, the Federal AE223 (55 grain FMJ 223 Remington) and Lake City M193 (also 55 grain FMJ), the M193 seems to be loaded somewhat hotter. If I had only a choice between those two, I’d rely on the M193 for defensive purposes.

And ultimately for most bullets and loads we have no better information than that provided by gelatin testing. The photo linked in the first post was unusual in that it was published at all. The vast majority of wound photos aren’t readily available for comparison, and the ones that are seldom include details about the gun or ammunition. There are somewhat more written descriptions, such as a doctor’s discussion of the horrible wounds he had to treat following the Parkland incident, but we don’t know the specifics, nor do we even know what ammunition was used.

quote:

Originally posted by sigfreund:
Thanks for mentioning the above incidents. They, plus the one described at the beginning of this thread, demonstrate the importance of adequate statistical data. A sample of one or two shows what can happen—but not what will always happen, or even what is likely to happen. This is especially true of complex phenomena like gunshot wounds. They involve many highly variable elements that will almost never be exactly the same among incidents.

Even when all the variables seem to have been minimized, things don’t always turn out the same. I once observed a factory-sponsored demonstration of the Hornady 9mm 115 grain Critical Duty load. Everything was as identical as possible: the same block of properly-calibrated “ordnance” gelatin, the same gun, the same shooting distance, the same box of ammunition. The first bullet failed to expand, perforated 16 inches of the test medium, and bounced off the backstop. The second shot expanded to a picture perfect mushroom with the so-called ideal penetration depth. Which one will get featured in the company’s advertising? Hmm …?

As both a shooter/retired military officer and medical practitioner, I could not have stated this better.
I have said to people many times in many formats, there will always be stories of spectacular one shot instant death or incapacitation incidents with 22 shorts or 25 automatics, and on the opposite spectrum incidents of lack of incapacitation with a body absorbing multiple 45’s or rifle rounds.
My brother as a retired detective can recall several incidents he investigated where a 22 or 25 got it done, while I was witness to incidents where people survived multiple torso hits from 7.62 nato and in one case a torso hit from a 50 bmg.
One simply never knows how a bullet or the body being hit is going to behave, regardless of how many statistics suggest a certain expected result

It's threads like this that reinforce my decision to stock up on M193 as my primary AR round. At the distance I'd be using for self defence, I'm not worried about barrier penetration or long range terminal ballistics. As always, YMMV.

quote:

Originally posted by snoris:
If it had been a .223 round (either "practice" or "duty") fired out of an AR-15 instead of a 5.56, how much different would the resulting wound have been?

If you mean an apples-to-apples comparison between otherwise identical .223/5.56 loads, any difference in effect on target of .223 vs. 5.56 would be negligible. While the case/chamber dimensions are very slightly different, the down-range performance will be functionally identical, if other parameters are the same.

However, 5.56 can be (but isn't always) loaded to slightly higher pressure than .223. This means that some 5.56 loads are capable of faster velocities than .223 loads. So in a non-apples-to-apples comparison, the slightly higher potential velocity of a certain 5.56 load may have a slightly different effect on target, compared to a slightly slower .223 load. (Similar to something like a 9mm +P load vs. a 9mm load, if you want to think of it that way.)

But again, just because it's 5.56 doesn't automatically mean it will be faster. It's just allowed to be slightly higher pressure/faster, and still be within the allowable safe guidelines for that particular chambering.