SF-OBC-556 Optimized Bolt Carrier Group for Direct-Impingement M4/M16/AR-Variant Carbines
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.