I put a 458 Green Mountion barrel on a mauser action and chambered it for 458 Lott and use black powder and cast bullets, What a HOOT to shoot. The brass are cheeper than 45-90 brass and hold about same bp. I fill the case up with FFg, use the lyman case cleaner tumbler to viberate powder down, put in a .030 card over powder and seat a 500 grainer. You need to clean the brass soon after shooting. I put a scope on the gun. Project was ment to find a bullet,load that shot good and latter put barrel on rolling block action. I have yet to try smokeles powder, Whin I do it will be A 5744