All good advice, thanks!
I have a 20-6.8SPC reamer on the way so I can set this barrel back and clean up the 204 Ruger chamber.
As 30 Rem brass is a bit scarce, I'll likely cut a rim and use 30-30 Win brass as the parent. Hoping for 4000+ FPS with 32gn pills. If I can exceed 204 Ruger performance, I'll be happy--but, for now, I'll just be happy to get this tube nice n' hot.