Machined by RCM from a Mil-Spec 41V50 Hammer Forged Blank. These blanks are considered to be one of the finest made. 1:10 twist, Nitride finish. Perfect for that HK build or to replace that shot out barrel. Each barrel counts as 1 US compliant part as an added bonus. Grenade rings machined into the profile to give it the look of a factory barrel. This barrel will require a MP5 Style Front Sight.