What are your suggestions for rings/bases? I intend to mount an older Leupold 3-9 x 40 on a Winchester Model 190 (after a trip back to Leupold for a parallax adjustment).

Warne 7.3 from Brownells. Make sure they are the 7.3 with 4-screws per cap not the 7.3/22.

Some complain about the caps scratching the scope tube but if you use some common sense it's easily avoided. The rings can be tightened to grip the hell out of the rail and not slip. If you're still worried about it you can cut, mill, or even file a groove in the receiver for a lug on the ring(s) to engage.

Or.........Burris Sig rimfire......#420-554 med matte 1"

Happy Thanksgiving !

http://www.burrisoptics.com/signature-rings