I have used my 2 Brownells (16 & 12) a few times.
I use a good grease on the shoe, I'll put it inside the barrel if I can reach it, to keep from galling.
You raise the shoe to just contact the dent, so it can't turn in the barrel. Then using a small brass hammer you tap around the dent until the shoe comes loose. Raise the shoe until it contacts and tap again. Keep doing this until the dent is raised to flush.
I have found that sharp dents usually will leave a small mark unless refinishing the barrels is in order. Some softer, rounder dents practically disappear.
Remember, the shoe doesn't raise the dent, it just supports it while you tap the metal around the dent back into place.
