SureFire SF-OBC-556 Optimized Bolt Carrier Group

Double Down on Reliability. Invented by Jim Sullivan, one of the original designers of the M16, the SureFire Optimized Bolt Carrier (OBC) doubles the reliability of any M4/M16/AR variant weapon system during suppressed and suppressed firing. Its patented design allows more time for reliable feeding of ammunition from the magazine and nearly eliminates bolt-over-base malfunctions. The OBC also delays unlocking of the bolt during the firing sequence, which allows expanding gases more time to exit the bore, in turn reducing back-pressure gases exiting the upper receiver group. Additionally, the neutrally balanced counterweight improves carrier and barrel extension lock-up, nearly eliminating bolt bounce. The OBC reduces felt recoil for better target tracking and greater weapon control when firing. Coated with an advanced anti-friction coating, the OBC resists friction during use and makes cleaning easy.

• SureFire's next-generation bolt carrier group, optimized for 5.56 mm/.223 caliber rifles and carbines
• The long-stroke design increases reliability when firing suppressed or unsuppressed
• Includes optimized bolt carrier, buffer spring, and long-stroke, H-weight buffer
• Designed by firearms industry legend and M16 designer Jim Sullivan
• Long-stroke design delivers 60% more travel beyond the magazine, increasing magazine feed time and reducing the chance of bolt-over-base malfunctions
• Dual-spring dwell weight significantly delays bolt carrier direction change for increased reliability
• Improved cam path delays bolt unlocking for a 15% decrease in chamber pressure before unlocking
• Self-lubricating, Diamond-Like Carbon (DLC) and S-Line coatings reduce friction for consistent, dependable operation in the most adverse conditions
• Mil-Spec bolt proof-tested and magnetic particle-inspected to meet the highest standards
• CALIBER 5.56 mm
• CONSTRUCTION Steel Alloy
• COATING DLC and S-Line Anti-Friction Coatings
• WEIGHT 13.6 oz (385 g)