I've been shooting Rugers for some time and I always go back to the original M77 with the tang safety. You can find them used for a very good price.
As far as cartridge, anything from 6.5x55 up to 30-06 should do without forcing you to deal with more recoil than necessary; however if you've been shooting a slug gun as you say, recoil doesn't seem to be a problem.
If I were you, I'd find a used M77 in 270 or anything else in the above spread and take the money you saved to buy a high quality scope. That should last you a lifetime.