KNS Precision KNS FIRING PIN RETAINING PIN PERMA AR15/M16 BLACK KNS FIRING PIN RETAINING PIN PERMA AR15/M16 BLACK Replaces standard cotter pin found in the bolt carrier to retain the firing pin as in original Stoner riflesWeight: 0.1 lbs.Dimensions: 5 x 6 x 0.5" MSRP: Was: Now: $8.50 Add to Cart