Id have to say my favorite of my groundhog guns is my Winchester Model 70 in .243. I reload and came up with a nice load using IMR 4895 and Sierra 85gr hollow point boattail bullets which is very accurate. The scope on it is a Leupold 3x9 which seems to be all I need since we have very few places to shoot much over 300 or 400 yards (that is where I go). I also regularly use a Remington 721 in 30-06 that my dad got years ago. Again I handload for it and have a sweet load using IMR 4895 and Sierra 180gr hollow point boattails. I know this is way overkill for groundhogs so I am playing with some Hornady 110gr screamers (3200 or 3300 fps I believe). They are of the ballistic tip design so maybe I'll get some red mist now
I am about to start loading for my 25-20, hopefully I can come up with a decent load for it to use out to 100 yards. If you have a .270 I wouldnt feel over gunned, just try a few different types of ammo and see which works best for you, then use it, if you reload you can load up some light bullets. Or maybe you want to use prarie dog hunting as an excuse for a new rifle...which to me is a pretty good one