The Judge is a gun with limited practical use. However, they are very fun. If you want one, get one (I did!). Using it like you have suggested will likey tear up your garden and not be very effective pest control to boot, in addition to being relativly expensive to shoot.
For your situation, I would look at one of theose scoped ruger .22 pistols. You could not really put it in your pocket, but you could easily carry it in a holster while working. With some practice, chipmonks would be an endangered species at your house. It would also be very inexpensive ammo wise when compared to .410 shells. The drawback is that those guns are a real pain to clean. Trust me, I know.
Happy hunting and be sure to google chipmonk recipes.