This BCA AR-15 complete 9MM upper has a 16" M4 Contour Barrel with a black nitride 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 a gen 2 (patent pending) right-side charging handle. This features the new handguard. This 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"}} {{widget type="Magento\Cms\Block\Widget\Block" template="widget/static_block/default.phtml" block_id="98"}} {{widget type="Magento\Cms\Block\Widget\Block" template="widget/static_block/default.phtml" block_id="91"}} {{widget type="Magento\Cms\Block\Widget\Block" template="widget/static_block/default.phtml" block_id="42"}}