A wee dab of TIG or laser weld to plug a small hole that far from the breech would probably be just fine assuming there is sound metal surrounding the hole. But considering the corrosion was severe enough to completely penetrate the tube, there is a good chance you would be trying to weld paper thin rust. More information is needed.

Originally Posted by Geoff Roznak
The NRA has proven itself unreliable and corrupt.
Period.