My dad used to shoot 'em in NY with his .222 bolt action. Wish I still had that gun but my a-hole ex-brother in law "cleaned" it up and sold it...bastard...
I grew up in small town Ohio right next to Amish country (Tuscarawas County). As kids we just understood that if you saw a ground hog you shot it. We did as much as we could with our 22 single shot rifles.
They also had the nickname of "whistle pig" - and sure enough once we learned to mimick their 'alert' chirp with a short whistle over our bottom teeth we'd get them to stand up for a good look around providing us a much better shot.
I'm not sure that the whistle is effective beyond 25-50 yards though - probably our "long distance" shots of the day!!