I made a set of expanding dent plugs for 12, 16 & 20 gauges on my lathe. They have worked extremely well for me.
I have told this numerous times before but once more. I bought an H grade Lefever parts gun which had a crack in the left barrel 14" from the breech. This gun had barrels of what Lefever described as "Best London Twist". The crack followed a weld line but did not appear to be an actual separation of a weld, just followed beside it. The appearance was that it had been struck on a hard object with a sharp corner which caused the crack & turned a section inward, inside the bore. Appears it was likely then fired with this inward obstruction which raised a flap on the opposite side of the crack to the inward flap. Probably enough pressure escaped to prevent it bursting.
Using my home made dent plugs I raised the inward flap & hammered down the outward one. The two sides fit back so perfectly I doubt any one would even notice the crack unless told specifically where to look & then it is very hard to see. Did "Not" appear to be any stretching of the metal at all.
After this I proceeded to fire (Remotely) several factory loads of 3�DE-1 1/8 oz loads & then several 3 3/4DE-1� oz factory loads. I then fired several 1 3/8 oz reloads. None of the above opened the crack at all nor did any sooty smudge appear on the outside of the barrel. That was a number of years ago & even knowing exactly where this crack is iit is hard for me to find it even all these years later. The entire bores of this gun were extremely pitted.
As I said earlier these old "Welded" barrels are simply not the "Death Traps" many have been led to believe
