This is my second use of the white lightning touch hole liner. The hole was drilled and tapped already - with a nice clean countersink. I inserted the liner until tight and the flange of the liner met tight with the barrel.
I proceeded to cut off the "tightening knob" and filed the excess off flush with the barrel. The ring around the liner was always there, (it did not "show up" after I started filing) so I filed just a little more thinking it was a just a lathe surface cut, and it's still pretty deep.
I removed the breach plug and the liner is right at the inside of the flat of the barrel in perfect depth for the rifling. I cleaned up any drill and tap flakes and excess, and reinstalled the breach plug.
This normal or OK? Does it weaken the liner? It's a swamped .40. Should I just replace it?
Any insight would be reassuring or informative - Thanks, Jon