I am not a welder by trade. With my first blank rifle I purchased a 5/16" diameter rod. All I did was file the end like a spade bit. I used my father's brace to power the new drill bit. Granted, there is very little room for wood chips so very frequent clean out is imperative. On another rifle I needed a larger diameter drill, so I just took the cutting torch and brazed a new drill bit onto the end of a chunk of cold rolled round. If you lay the drill bit and cold rolled on an angle iron inside corner they will line up. Alignment of course is the key here. Worked for me.The barrel channel maybe not so much. But the ramrod channel on a fusil with a barrel longer than 48" is going to make it tough to find a drill bit that long. And here I'm admitting that I don't know how to make one in my meagre shop. My guess is that it would take some welding skills I don't have, and some equipment that might be as expensive as the barrel, itself.