k2 Don't worry about shooting up your deck....If you happen to miss your only looking at a small dimple about the diameter of a wood match with maybe a little penetration.....order one online from cabelas and pop a few caps in their as*. good luck
Take a look at the nice air rifles Cabelas have, K2. I really like the Gamo rifles. they have a muzzle velocity of over 1000 feet per second. Should be plenty of power for a groundhog. You need a local sportsman to instruct you in the proper use and safety procedures. Of course, such a weapon would not be an adequate self-defense weapon. Check these out, and let me know what you think. trkyhntr http://www.cabelas.com/cabelas/en/templates/pod/horizontal-pod.jhtml?id=0005645&navAction=jump