I have a Ruger RSM in 458 Lott. I like it a lot (no pun intended) I had some trigger work done and a "real" recoil pad put on. And a mercury recoil reducer added in the butt stock.

My 500 gr. bullet load is

Fed. 215 primer
Hornady brass
Hornady or Woodleigh bullets (slightly different velocity and
impact points)
83 gr. IMR 4320

2248 FPS Hornady and I can't remember the Woodleigh speed, but it's a little bit faster.