JP Enterprises Enhanced Bolt Assembly .308 High Pressure With High Pressure Firing Pin Black. This bolt uses a specialized firing pin that is not compatible with other bolts nor can it use standard .308 firing pins. Specifications for JP Enterprises High Pressure Enhanced Bolt Assembly: Manufacturer: JP Enterprises Color: Black Finish: Black DLC Fabric/Material: SAE 9310 Steel Caliber: .308 Winchester Condition: New Projectile Caliber: .308 Caliber Package Contents: JP Enterprises High Pressure Enhanced Bolt Assembly JP Enterprises JPEB-308HP: Enhanced Bolt Assembly .308 High Pressure With High Pressure Firing Pin Black