This is a .38/9mm barrel blank. The outside diameter is .955" and the length is about 18 3/4 inches. There is an area about 3.360" that has been reduced to 0.800". The weight of a single barrel is 3 pounds, 1.2 ozs. This is a really useful barrel blank. Can be used to build barrels for many lever action and single shot rifles, pistol and revolver barrels and sub machineguns. Can easily make STEN, Madsen, Uzi and many other SMG barrels.