A New hampshire woodchuck in a horse pasture, about 30 years ago now. I was sitting in the back of a pickup, and using a Remington bolt action 30-06 with a 4X Weaver on it, the 'chuck was a tiny speck through the scope. The crosshair completely covered him, it was that small/far away. I held about a 'chuck's length above him and let her rip, and the faint "whap" a few moments later let us know I hit him dead center. It about vaporized his head, leaving only a rag of scalp and no skull at all left. We paced it off very carefully, twice, and came to 420 yards away. It was more luck than anything.
Shot a few dragonflies in half in my younger days with a Ruger standard auto. Those too, were luck.
Another NH woodchuck, 6 inch Colt .357, rested off a picnic table, 125 yards.
That about covers it. All these events occured years ago, I can't hardly see a woodchuck much past 125 yards these days.