I use John Biven's method on butt plates. Anneal the part, get a close fit, then use a ball peen hammer to gently bring the edges of the plate down to contact the wood, and then file smooth. Saves a lot of time, and Biven's had observed this method had been done on originals.
Don't toss a brass butt plate in the stove to anneal. They will melt. I know!
Don't toss a brass butt plate in the stove to anneal. They will melt. I know!