I use this system a lot to make barrel tenons. Cut sheet stock of any thickness you like...I use .032" to .0625", clean it with abrasive cloth, fold it double, hold about 1/8" in the vise, and bang the wings out flat. Flux and silver solder so they're one piece, place 'em upsidedown in the vise and cut the 60 degree for the dovetails, and set them into the barrel. I now have used steel, brass and copper. For this heavy rifle in such a small calibre, there will be no strain on the lugs, so copper will suffice, and it's easy to work.