The four designs featured some improvements over the M16A2, but not enough to justify ... Travis Pike is a former Marine Machine gunner who served with 2nd Bn 2nd Marines for 5 years.

A shortened variant of the M16A2 rifle, the M4 carbine provides the individual soldier operating in close quarters the capability to engage targets at extended range with accurate, lethal fire.

It works with the M4 Carbine, the M249 machine gun, and the H&K and M16A2 rifles. It is suitable for use in most weapons with a 1-in-7 barrel twist. The M855A1 has a copper-jacketed steel core ...