5.56 NATO M862 Short Range Training Ammunition (SRTA)
"Low" lethality, as opposed to "NO" lethality, intended primarily for live fire exercises against vehicles. Plastic, short range, high drag bullet, fired from conventional small arms. Beyond a specified distance from the muzzle, impact on tissue with the projectile would be painful, but not lethal. (Still presents a vision hazard, however.) To prevent confusion with conventional munitions, the weapon's bolt has a smaller case head opening, to prevent chambering a regular round, hence the special "S" in the cartridge headstamp. Case head is smaller than conventional ammunition. Note packaging is 30 rounds/box, instead of the more customary 20 rounds/box.