Shop › CMMG MK3 FIRING PIN RETAINER CMMG MK3 FIRING PIN RETAINER $1.95 CMMG Firing Pin Retainer, Fits CMMG Mk3/LR-308 Bolts, Silver 38BA4A9 Quantity: Add To Cart Added! CMMG Firing Pin Retainer, Fits CMMG Mk3/LR-308 Bolts, Silver 38BA4A9