I picked up a partialy finished custom rifle built on an original RB #1 action at a gun show few years ago. It was in the white, shootable and only needed a rear sight. The barrel is a new 45/70 tapered octagon 30 inches long, I don't know the manufacturer. The forearm was attatched with a single wedge, like many muzzle loaders are (Hawken style). When I got home I dissassembled the rifle and found that the wedge key was cut to go through a square slot in the barrel. This leaves a barrel thickness of about .100 at the key slot, it is 7 inches from the breech. I only shoot(REAL) black powder, would this be thick enough for black powder loads? Thanks, Ed