4x AO Bushnell Sportview did good work till I put a 6x36 Leupold on a 10/22. Using 6x and 2x7s right now.

Interestingly heard from a guy who uses an Anshutz sporter on squirrels, with a 3x. Not shooting long shots but says it works for him. I have used irons and also 2.5x.

That said, a 6x and 2-7 will do a lot of good work. If you have a heavy barrel it will steady better with a higher zoom, but something topping at 9 or 10x should give you plenty for what you are doing on squirrels, and the 200 yd targets.