KNS Precision AR15/M16 Firing Pin Black PERMA. These Bolt Carrier Groups from KNS Precision replace the standard cotter pin in the bolt carrier to offer a premium upgrade that's significantly easier to work with. Please note that the KNS Precision Rifle Firing/Retaining Pin does NOT fit .308 bolt carriers. Make your firearm maintenance a smoother and simpler experience by using this KNS PERMA Firing Pin. Specifications for KNS Precision PERMA Firing Pin Retaining Pin: Manufacturer: KNS Precision Color: Black Gun Model: M16 AR-15 Condition: New Dimensions: 5 x 6 x 0.5 in Country of Origin: USA Features of KNS Precision PERMA Firing Pin Retaining Pin: Replaces standard cotter pin Does NOT fit .308 bolt carriers Package Contents: KNS Precision PERMA Firing Pin Retaining Pin What firearm models does the manufacturer say KNS Precision PERMA Firing Pin Retaining Pin is compatible with? The manufacturer suggests that KNS Precision PERMA Firing Pin Retaining Pin is compatible with AR-15 M16KNS Precision PERMA: AR15/M16 Firing Pin Black