Having owned and worked on a lot of brass (but not to the degree of our experts... by a long shot...) I'd think your best bet is to get a PGP as a base. That way, the whole lower tube (12 gram/pierce pin/chamber/valve/hammer/hammer spring) can be kept intact and all you'll have to do is make sure the transfer port and feed hole are correct on the new barrel. It's bound to be a lot easier than trying to install all of that stuff in a bare tube.
Originally Posted by Hooligan
I found a way to make a sabot for a twinkie. The other tanks smell like banana cream filling now.