Kozzy, you're basically right: A bullet pushes you and the rifle back with the same force it has itself. However, the butt and the weight of the rifle keep this force from doing any damage by spreading the impact out over a wide area.
Picture this: a motorcycle hitting a car at 200mph, or a bus hitting it at 60mph. That's the difference between a 5.56 and a .45.
Regardless, who comes up with this "humane" BS. I'd rather be horribly wounded than outright killed. DUH.

Remember that we put limiters on our 5.56 assault rifle to save ammunitions....
A 25 round clip of 5.56 would be emptied in a couple of seconds in full auto...the bad guy is dead or dying but still up because of the high velocity...that was the problem leading to limiters (3 round bursts)...
In the good old time of 7.5 mmm rifle and 9mm submachine guns, a hit was a visible hit: target shaken at impact, switch targets!
Supersonic 5.56 trails a "big bubble" that indeed expand tissues to make its way through the tiny entrance hole the bullet makes...the damages made by that expansion are more extensive than they look....once entering the body, the bullet loses its balance (tissue resistance, bones) and tumbles and fragments, creating more damages.
A subsonic 9mm trails a smaller "bubble", slows down faster because bigger and slower and squashes against obstacles (bones they might break) or pushes stuff around (arteries....) without damaging them because not fragmenting (no sharp edge, no cut).
That is why it has been found that one is better off without a bad flak-bullet proof jacket that with it.
If hit in a flack jacket, the body armor shatters and the shrapnels follow the high velocity bullet adding to the damages. Nasty! the flak jacket ends up keeping the pulp together!
FYI, the 50 cal bullet impact force of a bullet passing through the meat of an adult pig's leg (closest to human flesh is the pig's flesh) shatters its thick and strong bone at 800m...

Well.i thought that in the cause of ear your goal is to KILL the enemy so i thinj that all this 5.56 is based on wrong conclusions

I may be wrong, I don't have a background in ammunition. But I believe Jamoni to be correct.

A 100% efficient round would transfer all it's energy in to it's target, causing maximum trauma injuries from the shock wave and pressure field of the round.

At the end of WWII it was found that most engagements were at an average range of 300m. At this range, 7.62 would go through the target, wasting energy (and therfore watsing the weight and volume of ammunition the soldier had to carry).

The British began to develop a round that was smaller than 5.56, I think it was 4.26, but this was deemed in-humane as it tended to inflict minimal damage, while causing alot of pain. When it was decided that NATO would adopt the 5.56 cartridge, we had to hastily convert the SA80 the this calibre. This led to alot of problems with the reliability of the weapon.

From what I've heard, the 5.56 cartridge was not desinged to kill, it was designed to "incapacitate" an enemy soldier. As it fragmented and tumbeled on impact it was supposed to injur the soldier. This means that if you hit one enemy soldier, insted of killing one and stopping one from shooting at you; you stoped the one you hit, and the 2-3 it takes to look after an injured caomrade.

The amount of energy does not kill you, it is the work done by the energy that kills you. The highly elastic and stretchy muscle tissue dissapates the energy well and no matter how big you make a bullet, but it will still penetrate enough to transfer it's energy over time (thus reducing the shock). It's the same thing with explosions the energy and pressue wave rarely kills people, its the shrapnel that does it. It takes a lot of raw energy to kill someone.

The number one thing is stopping power is shot placement, a 9mm to the chest is better then the .50 to the leg. The second factor is wound size, you want the deepest and widest wound that bleeds the quickest.

Couldn't agree more about shot placement. It doesn't matter what you're shooting if you miss. Of course you want a bullet to penetrate, what you don't want is for it to exit the other side with 90% of it's energy intact.

i dont know a great deal about ballistics info about small arms, i just shoot it, but what is the deal with this inhumane stuff? i didn't really know that war was supposed to be humane. well, in that case, i will go to my armorer and request goose down 5.56 rounds, so it doesn't hurt the enemy too bad.
someone correct me if i'm wrong, but doesn't a 5.56mm round tend to bounce around in the body before exiting?? just a question, no rhetoric.

some of these rounds are inhumane because they dont kill efficiently. if i was the enemy then the least you can do is kill me quickly. that is why i think we should use the 7.63mm mauser that explodes on contact and kills instantly.

It's the same thing with explosions the energy and pressue wave rarely kills people

lol Blast lung is the most common fatal injury among initial survivors. Secondary injuries are very common, and do often kill .. however, primary and tertiary (result of the blast wind) kill quite often as well.

Fair enough for me,as long as it does its job,its good for my rifle