Thanks for the comment. I don't believe it would apply to an Obermeyer barrel, but there are some barrel makers that turn off some muzzle swell in final contouring that's used to create a little bit of choke at the muzzle during fabrication.

In any event, thanks again, and here's hoping it shapes up to be a fun project. No doubt an interesting and desireable find, maybe someone can stamp the maker and barrel specs under the forearm of the finished project.