This AR-STONER Heavy barrel profile barrel has a pistol length gas system with a 1:24 twist. These AR-10 rifle barrels are made from the finest 4150 Chrome Moly Vanadium and precisely rifled for high accuracy at a great price. Use an AR-STONER.308 barrel in your next AR 10 build and experience superior performance. 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.