Years ago, when I used to engage in this foolishness, I would remove and replace pinned barrels using a plastic mallet. After removing the pin, I'd hold the revolver in one hand and strike the underlug repeatedly with the mallet until it unscrewed. I installed the new barrel the same way. This only works with underlugged barrels, like magnums and such.

If the barrel was within s few thousandths of clocking, I found it more accurate to carefully file the front of the frame instead of the barrel shoulder.

After wrestling with trying to set the barrel/cylinder gap with a file, I invested in a Brownell's cutter, which included a 90 degree face cutter and an assortment of forcing cone cutters. Much better.

I don't recommend these techniques to anyone, but they worked for me...

Tim