You can kill one with a .22 mag a lot farther than you think.Looking at the OP's rifle, I'm guessing he is reaching beyond .22WMR range.
Open ag field groundhogs dont let you get very close.
Used the 30-06 Accelerator's in the late 70's, early 80's. Killed a pile of Robertson, Simpson, and Logan county whistle pigs with them. Still got a full box somewhere. Moved on to the .17 Remington, 22-250 and 243. That's one thing I miss back here in Ga. When the soybeans got about 3-6 inches high the fun times were on. My record for one day is 31.Not near as many Ground Hog around here as there used to be. I bought a 204 years ago. It is deadly on them. Before that I used to shoot 55 gr accelerators in a 30.06 and killed quite a few with it too.
I been playing with the ground hogs a bit. If I miss one I change up guns. Missed this one with a .223 and a 22-250. The third time was the charm The 220 Swift sealed the deal