AR-15 Setup and Maintenance – Part 2, by John Smith
(Continued from Part 1.) Ammunition For Your Rifle Ammunition selection is an important topic to discuss. M193 55gr 5.56mm NATO ammunition was the early military-issue ammunition. Back then, M16 rifles had 20” barrels and the 55gr bullet did devastating damage yawing and tumbling after the initial impact. However, after the 20” barrel was retired for the 14.5-inch M4 barrel, the effectiveness of the 55gr M193 decreased. This was due to the decreased muzzle velocity from a much shorter barrel on the newer variants of the M16. I have no problem with using 55gr ammo. However, I would suggest using at …