While searching around I found a thread that asked the opposite question. "What's the smallest round you've used on the biggest game," And I thought this might be an interesting question as well (and maybe even a bit more legal ). I saw a webpage once detailing a gentleman's exploits hunting groundhogs with a .44mag (claimed .357 didn't give reliable one shot stops). So fess up... who's shot a woodchuck with a .300 magnum... I know somebody has. BTW if somebody is familar with the site I mentioned I'd like to find the link again. I believe the guy called himself "the terminator" or some clever groundhog related version of that.