5.56mm velocity and pressure vs barrel length study.
- Thread starter Diamondback 2/2
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That study seemed fairly indepth, especially with the chamber pressures at exit and the impact of a suppressor. To me it did seem like they lacked some definitive evidence of proof on some statements. This statement stood out to me when they provided no further evidence, "M855 bullets traveling below 2,500 fps when impacting a target will not produce a lethal wound channel."
That's a pretty general assumption on their part. It depends on where it hits you.
Great find, BTW, @Diamondback 2/2
Yeah I agree, you put a M855 in the right spot, 2500fps or not, its lethal.
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Or what exactly drives the conclusion that 2500 fps is the magic cutoff. That statement caught my eye as well - Is it a specific probability of a hit being lethal below that speed? Or is there some ballistic effect that occurs below that point? I agree with @AKkeith that without further explaining it, just positing it as fact is a bit dubious.
I imagine it has to do with the internal wound cavity with regards to the high velocity tissue expansion. But that's just a guess, as I'm not aware of any ballistic gel tests that are specific to M855 and 2500 fps velocity at impact of the gel.
We all know that 5.56 works by high velocity coupled with tumbling and fragmentation of the bullet. But at what speeds are required for those effects to take place, I'm unsure of. That said, a 36gr .22cal moving at 1,000 fps has killed many of people. So it's doubtful, to me anyway, that a 62gr .22cal bullet moving at 2.5 times that speed will not produce a lethal wound when fired at a vital organs or the brain housing group.
$.02
We all know that 5.56 works by high velocity coupled with tumbling and fragmentation of the bullet. But at what speeds are required for those effects to take place, I'm unsure of. That said, a 36gr .22cal moving at 1,000 fps has killed many of people. So it's doubtful, to me anyway, that a 62gr .22cal bullet moving at 2.5 times that speed will not produce a lethal wound when fired at a vital organs or the brain housing group.
$.02
Florida173
SOF Support
Aren't we all using m855a1 now?
USMC is still using M855, but yes Army is M855A1 currently. The M855A1 is supposed to be a hotter round making up for the shorter barrel in the M4, but that's all after my time so I don't know much about it.
Come on @Florida173. Not all of us are high speed. The Marine Corps is just getting the M4. We are still all excited about how cool they are. Slow your roll.
Brill
SOF Support
300 AAC baby!!!!
He says the shorter barrel has a higher muzzle pressure (not a surprise by the way, muzzle brakes work better on shorter barrels for a reason) but the same 7 inches of "dwell" is appropriate for a 14.5 and 20 inch barrel? Not to mention if you just take the literal meaning of the word dwell, port distance from the chamber would be dwell and distance from the muzzle more of a port open time. Then there's the mass of the BCG/buffer and the actual port size.
Nope ole Eugene was perfection, can't change anything; it's like changing the 1911, except when Browning changed it, that was ok.
Nope ole Eugene was perfection, can't change anything; it's like changing the 1911, except when Browning changed it, that was ok.
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It's been proven more than a couple times over that a .22 LR is a lethal round, even while moving quite a bit slower than that.
Getting a hole poked in you, regardless of speed or size, is never a good thing- the academics need to quit trying to tell us otherwise.
I seem to recall pics of the IDF using Ruger 10/22's as a terrorist elimination tool.
They actually use it for crowd control, using sub-loads to the leg of a protester. Not lethal, but gives you an accurate stand off distance. About the equivalent of a high powered pellet rifle.
Brill
SOF Support
Pashtun boys have said this for decades now.
I hate myself for Liking the accuracy of this statement.
Brill
SOF Support
Would the womenz in his life agree or disagree?????
Apparently at our recent rifle trials (NZDF) they found some of the 14.5's more accurate than some 20 inch platforms out to 600m. Navy and Airforce are going with LMT MARS-L's with 14.5 inch, Army is going with 16 inch and it is apparently to do with the difference in terminal ballistics at 600m of the two. NZ Army Manoeuvre/Combat trade weapons qual with ACOG goes back to 600m.
I think you have misheard/misunderstood something, because its scientifically impossible. Shorter barrel equals lower velocity, lower velocity equal less consistency during external effects (wind humidity, etc, etc). If you use the same rounds in the same quality barrel, one being 5.5" shorter has done nothing but reduced the velocity on the round.
On top of that, if that was the case, Camp Perry National Matches, and primarily the President's hundred, would be shot with tricked out M4's vs NM AR15's (M16 without the selector) and M1A, etc.
But please do post the study if you have the link, I'd like to see what was done to come to such conclusions.
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