RCM is now offering a Cold Hammer Forged 41v50 Barrel Blank. This is Chambered in the 5.56 NATO Caliber and Fluted to the Latest Specs. Each Blank like all of our Barrels has to pass a Back Flow Pressure Test. This Ensures that Our Flutes Flow the Same amount of air as the Factory Barrel does. The RCM CHF Blank is 18.500 long with a qualified .990 OD to the bore. If you ever wanted to do a Custom Profile of your Own, This is the Best Option out there.