This is a new Barrel with gas block. This barrel is 21" and the finish is great. This barrel was bought from thegunpartsguy.com back in 2007-2008 as a spare and never used. I realize now that I don't shoot much .308 and the risk of shooting out a barrel is slim to none. There are no markings on the barrel. The crown and rifling are what you would expect from a new barrel.