I never said an AR-15 was or was not lethal but as you brought it up, it most certainly is often lethal to small to medium sized, thin skinned mammals. My point was and is that the AR-15 is NOT chambered in a very powerful, particularly lethal cartridge, nor even one near the 'middle of the pack' of commonly used firearm calibers for normal, US hunting and target shooting. A typical LEO's .40 S&W, loaded with hollow points and used for a solid torso hit would would be, in my opinion and experience, far more destructive than . 5.56 NATO projectile in the identical place on the identical target, at least at close range (under 100 yards).
No. Another myth perpetuated by.... I have no idea who we have to thank for that one. No firearm purposefully uses a single projectile, long gun or short gun, that tumbles, nor have they ever done so as it would be a particularly ineffective thing to do.
If the bullet 'tumbled' in flight, it would do what is called 'key-holing' in targets (where the perforation is not round but elongated from the projectile passing through on its side.... leaving a penetration that looks like a 'keyhole'). Further, the only way a projectile of any kind can travel appreciable distances, with any accuracy, is if it travel along its axis, any appreciable 'wobble' is hugely detrimental, actual tumbling would effectively ruin the projectile's flight as well as use the projectile's kinetic energy at a fantastic rate, rendering the projectile far less effective in relatively short distances (less than 100 yards and it gets much worse as the distance increases). Please note that I did not say a tumbling projectile was not dangerous, merely that it is never, ever done with conical projectiles from long guns or short guns on purpose.
In fact, the only firearms I have ever seen do this are handguns in large diameter calibers, usually using lead bullets and 'leading' the barrel so badly that the rifling can no longer be seen. By the time tumbling actually occurs, accuracy is so poor that is it often necessary to move to a very short distance (under 10 yards) to the target to even be able to hit something the size of a target. And once that is done, the 'key-holing' obvious (the hole in the target is of a projectile sideways or close to that shape).
High velocity bullets can cause hydrostatic shock but again the AR-15's cartridge is well down in the range where that becomes important regarding lethality. The same .22 caliber projectiles driven from a .220 Swift (obsolescent now), 22-250 or a host of other, readily available and often used sporting calibers will easily add 30% to the projectile's velocity and begin to become effective through sheer velocity rather than velocity coupled with projectile weight and / or bullet wound channel size (caused by expanding bullets, which again, the AR-15 usually does not use although it certainly can). And again, a .30 caliber bullet traveling <nearly> as fast as a .22 caliber bullet will simply do more tissue and especially hard material (bone, cartilage) damage than the smaller bullet as well as penetrate far more.
If you want to read some interesting, in- depth accounts of calibers and their various wounding abilities, read the US gov't reports generated in the 1930's before the 30-06 was re- adopted for use in the then- new M1 Garand. A smaller, faster round was tried with mixed results and in the end rejected (a .276 diameter if memory serves). The reports are truly grisly but what else would one expect when studying gunshot wounds and trying to choose the most effective (read: the most tissue damage w/in reasonable restrictions, meaning that the average person can become proficient with that size caliber) caliber / velocity / projectile type and shape.
All the way back to the topic at hand: I am merely trying to bring some facts to a topic often skewed in one direction or the other by the various factions. All that I have said is easily verified by reputable sources, perhaps most notable the ordnance boards of the various US armed services over the years.
Brian
A firearm does not have to be powerful to be lethal. I have read some medical accounts to the effect that the 5.56 inflicts massive damage on human tissue realtive to its size. And this reminds me that an AR-15 fan friend of mind once told me that the round is so deadly because it tumbles in flight or on impact. Any truth to that?