I recently purchased an old Marlin 39A in fair/good condition. The only thing that I haven't figured out how to fix is the aforementioned magazine tube support ring. It's dovetailed into the bottom of the barrel, but it is so loose that you can easily push it either way with your fingers. If the tube was out, the ring would fall out.

I've thought of JB Weld, but you have to be able to remove it. I considered peening the barrel next to the dovetail cut, but this would scar the barrel. Shims might work, if I can keep one (or more) from falling out.

Any suggestions?

LT

Suggestion only, as I've never tried this. How about a couple drops of blue Loc-Tite applied to the clean mating surfaces?

I have repaired many dovetails by judicious use of a hammer and punch and never marked the blueing. Your mileage may vary.

Build up the bottom of the ring with solder, then sand away a little at a time until you have a snug fit, then tap it in place.

Goatwhiskers & M1894 both have good suggestions but you can also just prep and solder it in place, use a low temp silver solder, be very careful with the amount of heat you apply or you'll wreck the bluing and or warp the bbl.

If it was mine, I'd opt for peening the dovetail and leave the dovetail slot alone. This will tighten it up but all the marks will be hidden within the slot and not visible unless you disassemble the connection.