This BCA AR-15 complete .450 Bushmaster rifle length upper has a 10.5" heavy barrel with a parkerized finish, and features a 1:24 twist rate, with a carbine length gas system. It includes a 10" MLOK rail, an M4 flat-top forged upper receiver, a BCA bolt carrier group, a flash hider, and a rear charging handle. This .450 Bushmaster upper is compatible with any mil-spec AR-15 lower. Shop more .450 Bushmaster Uppers! Magazine not included. 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"}}