This BCA AR-15 complete 9MM rifle length upper has a 16" M4 barrel with a parkerized finish, and features a 1:10 twist rate, with a blow back gas system. It includes a 15" MLOK rail, a branded M4 flat-top billet upper receiver, a BCA bolt carrier group, a flash hider, and right-side charging (Gen2) handle (patent protected). This BCA 9MM upper is compatible with any mil-spec AR-9 lower. ALL OF BCA 9MM UPPERS ARE DESIGNED FOR USE WITH GLOCK STYLE MAGAZINES.Shop more 9mm Uppers!Check out Magazines here!{{widget type="Magento\Cms\Block\Widget\Block" template="widget/static_block/default.phtml" block_id="56"}}*Note - We strive to provide the most accurate photographs of our product. Variations may occur in the skeletonized section of the handguard/flash hider you receive.{{widget type="Magento\Cms\Block\Widget\Block" template="widget/static_block/default.phtml" block_id="42"}}