I've only shot two groundhogs in my life, both lung shots techically, one between 8-10 lbs and one probably getting close to 12 lbs. They were digging up around my barn, got one in daylight at 85 yards with 357 texan shot square through center of chest as he was standing looking at me, out center of his spine. And one late at night with Trijicon thermal scope on a suppressed Ruger 17hmr a few days later, broadside through lungs no exit. Neither twitched, although the one with the Texan did have a front paw straight up in the air on it's back and the paw over 2 or 3 seconds slowly dropped to it's chest.
