Use the longest barrel 22 you have. I am lucky to have a CZ 452 with a 29" barrel. BTW, I cannot shoot the calibre or the little 6mm RWS as they don't make it out the barrel!!!!
CB longs are my favorite!! VERY accurate!! As long as you keep the range short, say 20-25 yards and limit the shots to head shots, even big Wood chucks can be cleanly harvested.
At least, I have about 10 or so less chucks and a dozen or so squirrels around here from such an outfit!!
In may last house, I had a BIG problem with chucks in my garden. I also had a tree-hugger neighbor who didn't kill flies!!
I was out one day spreading insect killer on the lawn. She threw a hissie fit. (Our lawns adjoined.) She was worried about the dogs, both hers and mine. I told her to keep them in the front yard for a couple days and after the first rain everything would be just fine. I had done this for years she needn't worry.
About a week later a huge chuck waddled into the garden and the wife called me over to shoot it. I waited and waited but he never offered the perfect shot. I had been after this one for the better part of a month and he wasn't leaving the garden under his own power this time!! Well finally he sat up with a hand full of greens and looked right at us. I put the front site on his nose and squeezed, pop, went the gun and plop went the bullet. I heard the bullet smack 'em. Over he went and he was scrambling out into the neighbors lawn just that fast!! Now I KNOW I didn't miss... I herd the bullet hit!?! All I could figure was the bugger was tougher than the CB longs 29gr bullet. Any how he made it across the yard and into the woods so I figured, fine, I'll go grab him later after dark and bury him. Well... I forgot...
The next day that neighbor came over to my wife complaining about that bug killer and how I had promised her it wouldn't hurt the animals. Well... she had just found that chunky chuck and he was stiff and quite dead. SHE was positive it died from eating our poison grass. That night her husband and I had a beer and a laugh on my deck!!
Be safe, don't take any chancy shots and DONT TELL anyone!! You will be fine.
CW