For out to 150 yards on an animal the size of a woodchuck, I would go with .22 hornet, or maybe a tad bigger, up to .223 remington, or somewhere in between (.221 rem fireball, .222 rem, .218 bee, etc.). .223 rem is more than enough power, laser flat to 150 or more, and cheaper to shoot. But for less noise & recoil, I'd look at .22 hornet or .218 bee. Or the .222 remington also as a possible alternative - it's a very accurate cartridge, and used to be extremely popular for varmints and benchrest shooting, prior to the creation and popularization of the .223 rem. The .222 has a longer neck which allows the bullets to be very stable/straight in the chamber when they hit the rifling, which aids in good accuracy. A .17 hmr or .22 mag rimfire would work, but it's arguably a tad on the light side for woodchuck. Going with anything bigger than .223 is pointless under 200 yards.