This BCA AR-15 complete .450 Bushmaster rifle length upper has a 18" heavy barrel made from 416R Stainless Steel, and features a 1:24 twist rate, with a mid-length gas system. It includes a 15" MLOK rail, an M4 Billet upper receiver, a BCA bolt carrier group, a flash hider, and a side charging (Gen 2) handle (patent pending). 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"}}