M855 ammo is differentiated from M193 ammo by two characteristics: 1. The bullet weight of 62 grains instead of M193's 55 grain bullet. 2. The steel in the jacket of the M855 projectile. Note that M855 rounds are magnetic and you should not use 5.56x45mm ammo in a .223 rifle unless it has been tested and approved to handle this pressure by the manufacturer.
Review by FROGGY
Posted On: 11/19/15 By: Jason
Posted On: 11/15/15 By: Leif Magnusen