The true RSM was never manufactured in 458 Win Mag. The RSM is a Mark II. But has an integral quarter rib machined in as part of the barrel. Pretty unique and special feature of that model. And the word is that Ruger lost money on each and every one. But built them because Bill wanted to, and could afford to. The RSM also has a few other special things about them.
The 458 Win mags I've seen are older model guns prior to the Mark II. No quarter rib. Nothing special.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.