So here is a brief report on weapons some U.S. sodliers put together in Iraq. There is a much longer version (5-6 pages) of this but I just wanted to include these two:
1) The M-16 rifle : Thumbs down. Chronic jamming problems with the talcum powder like sand over there. The sand is everywhere. [The Marine] says you feel filthy 2 minutes after coming out of the shower. The M-4 carbine version is more popular because it's lighter and shorter, but it has jamming problems also. They like the ability to mount the various optical gunsights and weapons lights on the picattiny rails, but the weapon itself is not great in a desert environment. They all hate the 5.56mm(.223) round. Poor penetration on the cinderblock structure common over there and even torso hits cant be reliably counted on to put the enemy down.
(thats dissapointing)
2) Mostly AK47's The entire country is an arsenal. Works better in the desert than the M16 and the .308 Russian round kills reliably. PKM belt fed light machine guns are also common and effective. Luckily, the enemy mostly shoots like shit. Undisciplined "spray and pray" type fire. However, they are seeing more and more precision weapons, especially sniper rifles. (Iran,again)
(thats even more dissapointing)
So why does the U.S. keep using this same size round?