groundhogs correct? that's what we called them back east. there seems to be differences between the states what is a whistle pig, ground hog, ground squirrel, gopher and prairie dog!
some of the ground hogs back in IN in the bean fields were BIG and we took them with a .22-250 from the way back fence. When i go to Seligman,AZ for prairie dogs (thousands of them) use a .223 since you are a ways off, aside from Caddyshack, differentiating a gopher from a ground squirrel maybe my issue!!!
is that a PEPR mount on your gun? I took off my EOtech w/G33 and put on a different AR, and was running a C-More railway on the 15-22. great for steel comp but for hunting not so much. i have a very nice high dollar FFP 1-4 in a PEPER mount but it is pretty heavy and kind of negates the lightness of the 15-22 for taking afield for bunnies or whatever.
i may have to change it out from the C-More to the 1-4 since we don't shoot much in the summer here.