This BCA AR-15 20" heavy barrel has a black nitride finish with a 1:9 twist rate. It is chambered in .223 WYLDE and has a rifle length gas system. All finished barrels go through a 100% inspection process. Inspections Equipment includes CMMs and Air Gauges for the bores as well as visual and machine inspection. Shop more .223 Wylde Barrels! {{widget type="Magento\Cms\Block\Widget\Block" template="widget/static_block/default.phtml" block_id="42"}} It is the responsibility of the consumer to ensure all state, local, federal, and ITAR regulations are followed. Does not include gas block or gas tube