From the infantryman’s perspective, he attempts to fix the enemy, since his equipment limits his ability to maneuver, and attempts to kill the enemy through close air support (CAS), close combat attack, (CCA) or indirect fire.
The infantryman’s ability to fix or kill the enemy with organic weapon systems at distances beyond 200 meters is limited by his equipment and training. The incapacitation mechanism of small caliber bullets, such as the 5.56-mm, comes primarily from bullet fragmentation. Bullet fragmentation occurs only at a sufficiently high velocity. All 5.56-mm weapons are most effective when employed within 200 meters due to velocity limitations. Once contact is made, the fight is limited to machine gunners, mortars and designated marksmen. In the table of organization for a light infantry company8 only the six –M240B 7.62-mm machineguns, two- 60-mm mortars and nine designated marksman armed with either 7.62-mm M14 rifles or accurized 5.56-mm M16A4’s rifles are able to effectively engage the enemy. These weapons systems represent 19 percent of the company’s firepower. This means that 81 percent of the company has little effect on the fight. This is unacceptable."
(с)"Increasing Small Arms Lethality in Afghanistan: Taking Back the Infantry Half-Kilometer" Major Thomas P. Ehrhart [United States Army Command and General Staff College]