I confess. I've used JB Weld on three doubles that were missing plugs. But all three guns were just common guns. Two had been cut to "coach gun" length before I got them. Maybe a bit utilitarian but after a bit you would be hard pressed to notice that it was a cheap and easy fix.
On a Stevens 311A that had been cut to 18", I took advantage of plug being missing and filled the void under the rib with lead shot. This replaced some of the weight removed when barrels were cut. The gun is now used in Cowboy Action Shooting.
I take a Swiss file and clean up the hole and clean off any oil that may keep JB Weld from bonding. I stuff a little wad of steel wool down the hole to form a dam and then fill with JB Weld.
