David,
The lug being made of 1020 is not unreasonable. The stresses are low on it. Barrels are a different thing altogether.

That fella likely performed a conductivity test. It works well for identifying aluminum alloys but I 've not heard of any simple non-destructive test for steel alloys. The issue I see in welding this gun is the cracking of the weld I encountered with my sleeving project. If you don't encounter that or overcome it, it might work out.

Last edited by Chuck H; 01/27/12 09:43 PM.