I spent 15 years chasing groundhogs in South Central PA and did 90% of it with a .223 and never felt undergunned. Arm yourself with good optics and rangefinder, and learn to dope the wind and a .223 will serve you well.
If I were to get back in that game I would unlimber the current .223, a Browning Low Wall, and have at it. Or the .22 K-Hornet M54 Winchester if I didn't feel like walking as far. Starting from scratch I would build another .219 Donaldson Wasp on a High Wall and skate through my Golden Years with a big grin on my face.
