The BCA AR-10 Barrel is a 20" heavy barrel profile made of 4150 chrome moly vanadium stainless steel, rifle length gas system with a 1:8 twist rate and is chambered in 6.5 Creedmor. All Finished Barrels go through a 100% Inspection Process. Inspections Equipment includes CMMs and Air Gauges for the Bores. BCA's expectations is that our Barrels, 16 inch or longer, will hold a 1.000" MOA at 100 yards with appropriate ammo and shooting techniques. ALL NFA LAWS APPLY