I was gonna buy the Brownells lug cutter, but decided to file them.We formerly used a torch and GI magazine spring to build up lugs and hoods...still would sometimes end up with a carbide clump that would knock the teeth off a file. Nowadays, even a true GI magazine is getting harder and harder to find among all the fake ones, so no living in the past, even if someone wanted to do that. I don't know who invented the lug cutter for perfect mating of lugs with stop for particular frame/slide/barrel, whether Air Force gunsmiths for the team at Lackland, or somebody else, but Bob Day (Distinguished shooter and retired team gunsmith) in San Antonio certainly had one in his shop in the mid-70s, and HE learned from masters.
If I was doing a lot of barrels I would definitely get the lug cutter.
Joe