1:10 twist. Brass is new, but was left over stuff a local gentleman had purchased it in 1984.

I've tried about 10 different powder, charge, bullet combinations all with 150 or 155 grain bullets from Hornady, Sierra, or Nosler. Noslers being least accurate, Sierras the most. I'd like to stay lighter for deer sized game, but next option will be some heavier options from Sierra, Berger, and Hornady. Everything I've tried so far indicates that this rifle favors IMR4320.

I'm certainly not giving up, just trying to gather some additional ideas that I may not have looked into. Though at some point, I will likely rebarrel as I'd prefer a 24" tube for a little better burn.