A 22LR at 200 yards requires a LOT of elevation adjustment in your scope. Something like 25 minutes from a 50 yards zero with standard velocity ammo if memory serves me correctly. I know on my Browning T-Bolt Match/Target rifle that's topped with a Vortex Diamondback 6-20x44mm Mil-Dot scope, I don't have enough elevation adjustment (2 minutes shy IIRC). As a result if I want to shoot 200 yards with it dial in 20 minutes and then hold-over using one of the dots for the difference. What I really need is a 20 MOA base, but I figure if I want/need to shoot something at 200 yards I have several centerfire rifles in .223 Rem. that would be better suited for that job.

Soo...if you want to shoot 200 yards with a 22LR you're going to want a 20 MOA scope base and a good scope that offers at least 60 MOA of total elevation adjustment. Can't find anyone who offers 20 MOA rail for the Model 64 so you're going to have to focus on the scope.