What Colt AR 15 Ammunition is Better?
5.56mm NATO chambered rifles will reliably function with either 223 Remington commercial ammunition or 5.56mm NATO military M855 62gr ball or older (Pre-1982) 55gr NATO ball ammunition. Firing 5.56mm NATO ammunition in a 223 Remington chamber can lead to pressure related problems due to tighter neck dimensions in 223 Remington chambers and thicker case walls in 5.56mm NATO spec brass. Some of the problems related to pressure are the possibility of blown primers, ripped case rims leading to extraction problems and excess wear and tear on internal parts possibly leading to parts or weapon failure. Any ammunition intended for street use must be tested for reliability in any gas operated weapons. Barrel lengths and gas port setup make a difference in reliability from commercial AR15 and military M16 setups. Generally most AR15/M16 based rifles come with either a 1 in 9 or 1 in 7 twist barrel. The 1 in 7 twist barrels will allow the use of 40-80 grain projectiles. Currently 80 grain project
