Years ago i saw an article in Guns & ammo annual where a Mauser broom handle pistol was restored. It was so heavily pitted & worn it was little better than a relic. The gunsmith filled individual pits with Tig weld & built up all the edges with Tig welding before remachining the corners & surfaces, the finished pistol was superb & could not be distinguished from a new one. The cost was astronomical but showed what is possible.