It sounds as if you know the gun!

I do not know the exact location, but he said it was in a spot that would be bad news if it ruptured, so even though he shoots low pressure loads exclusively, he would probably always be a bit nervous while shooting, and that is no fun.

We'll do a double check on the measurements, but .018" (I believe that is what he told me) would make me nervous, too! Even if it did not blow out, that thin a tube would be highly likely to get dented in normal field use (although my guns don't see that, the next owner might not have the same orientation I have).

Titanium Briley tubes should work just fine and it would become a 6 1/2 pound or slightly less 20 gauge.