And to measure your barrel at the 20” length you desire not at the current muzzle. Should have said that in my first post. I have a first gen mark ii barrel stainless and it is the slimmest Ruger mag barrel I have ever seen. Measures .620 at the 20” mark. That would leave .081 on each side of the bore. Don’t know if that is good enough or not.
Ruger had a few profiles on their mid magnum rifles.
