If you are a good shot & have confidence in your gun at that distance, I would put one behind the animals ear. Are the coons giving you trouble? Do you live in the boonies enough to not get in trouble for the discharge?
They are actually pretty tough critters. I shot one 14 times once; just stood there while I wholloped it with a full tube from a henry golden boy. I could hear every shot thump as the hit vitals, and the animal just sat there like I was missing it. I am sure it was mortally done for, but I still grabbed the SKS and that was that.