JP Full Mass Operating System Bolt Carrier - Large-Frame (.308) - Stainless Steel - QPQ Black Finish - Our full mass .308 carrier is designed to provide greater reliability in suppressed setups as well as SBRs and rifles without an adjustable gas system. Heavier than a standard DPMS LR-308 carrier the JPBC-5 allows for the additional cycling delay required for reliable function in such setups. - This design incorporates forward assist serrations making it compatible with both DPMS and Armalite rifles. Each carrier also includes out Enhanced Gas Ring for more reliable function. - Requires DPMS-pattern bolt firing pin and cam pin. - For a complete operating system this carrier pairs best with the JPSCS2-10H2. - Weight: 15.31 oz. with key installed.