I suspect a 2x-7x would be adequate. However, I shopped around and found a Nikon 3-9X40 at an attractive price three years ago. It's what I have on my benchrest gun now and I love it, I started benchrest 7 years ago with a 3-9X40 BSA "Sweet 22" (in my experience a seriously underrated scope) that I now use on a 10/22 I keep for Rimfire Challenge matches.
I have old Leupold 2-7 scopes on two rifles. I bought a Nikon 3-9 with BDC for the 22 rifle I use most. The 3-9 is definitely an upgrade in most ways, though I doubt it'll last as long as the Leupolds have already lasted.
Nikon or bushnell has a 3x9x40 with BDC reticle rim fire scope. It's pretty pathetic that I can't remember since I own one but I use it to 200 yds without any problem.