The .50 Caliber Mk 257 API - DT has a purple bullet tip. The bullet has a hardened steel core and incendiary tip. The .50 Caliber MK257 is used in machine guns M2 , M3 , and M85 .
The .50 Caliber Mk 265 has a black tip. The bullet has a hardened steel core . 
 It is used in machine guns M2 , M3 , and M85 .