SureFire Optimized Bolt Carrier Group Spring for M4/M16/AR-Variant Rifles & Carbines

SureFire Optimized Bolt Carrier Group Spring for M4/M16/AR-Variant Rifles & Carbines. Its patented design allows more time for reliable feeding of ammunition from the magazine and 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 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. NOTE: Only Spring Specifications for SureFire Optimized Bolt Carrier Group Spring Only: Manufacturer: SureFire Fabric/Material: Steel Alloy Caliber: 5.56mm Gun Make: AR Platform Gun Model: M16 M4 Weight: 13.6 oz Bolt Material: Steel Alloy Carrier Material: Steel Alloy Features of SureFire Optimized Bolt Carrier Group Spring Only: Designed by firearms industry legend and M16 designer Jim Sullivan Long-stroke design delivers 60percent 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 Package Contents: SureFire Optimized Bolt Carrier Group Spring Only What firearm models does the manufacturer say SureFire Optimized Bolt Carrier Group Spring Only is compatible with? The manufacturer says that SureFire Optimized Bolt Carrier Group Spring Only is compatible with M4 M16SureFire SF-OBC-556-SPRING: Optimized Bolt Carrier Group for M4/M16/AR-Variant Rifles & Carbines