Invented by Jim Sullivan, one of the original designers of the M16, the SureFire Optimized Bolt Carrier (OBC) is designed to improve the functionality of an M4/M16/AR variant weapon system during both unsuppressed and suppressed firing. This patented design makes numerous improvements to the standard Mil-Spec full-auto bolt carrier group which allows more time for reliable feeding of ammunition from the magazine, nearly eliminating 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 also reduces felt recoil, allowing for better tracking of sights and more control of the weapon when firing. Coated with an advanced anti-friction coating, the OBC resists friction during use and makes cleaning easy. For the ultimate in reliability, choose the SureFire OBC.
- Neutrally balanced counterweight automatically reduces cyclic rate, negating the need for switch or setting adjustments.
- Improved cam path delays unlocking, allowing the chamber pressure to drop another 15% which permits more gasses to exit the bore
- Nearly eliminates bolt bounce
- Long stroke design improves reliability, allowing ammunition more time to feed properly
- Utilizes Mil-Spec bolt and components
- Anti-friction coating resists corrosion and makes cleaning easy
- SF-OBC-556 comes standard with Optimized Bolt Carrier, Long-Stroke Buffer, and Improved Buffer Spring