Lord, I don't know, Coyote at 350+ was my longest than I can think of. As far as "best", I've shot a lot of deer on a dead run jumping 'em, rabbits, too. I love to hunt that way where I can like out in West Texas, still hunting and walk and stalk from ridge lines. I remember one rabbit on a dead run at 40 yards with my .22 that I impressed myself with.
That there bunny was MOVIN'. But, I guess it'd have to be a snake I shot once. I was fishing this little lake in the hunting/fishing club I was in at the time. It was infested with water snakes of the genus Natrix such that they HAD to be hurting the fish population, though there were a lot of crappie in that lake as well as black bass. I had a Phoenix Arms HP22 in my pocket. Now, you might think this little pot metal gun is a POS, but the thing is 3" accurate at 25 yards with it's SHORT barrel, amazing little gun, why I like it. Fits in a pocket and I can take it anywhere with that sort of accuracy. Amazing. Anyhow, I saw a BIG snake on a log, just could see the body, was about 25 yards. I shot it center mass, it rolled off that log, came up and saw me in the boat and started after me front half of its body out of the water. These things are aggressive if not poisonous. I started shooting at its head as it occelated back and fourth and hit it square on about the fifth shot about 20 feet from the boat. I was getting ready to go hand to hand, but concentrating hard on that front sight. ROFL! What they call close quarters combat. I also hit one swimming that day about 25-30 yards out. That was a lot of fun, caught a few fish and killed a dozen or so snakes that weekend.
I don't think I've ever seen a lake so over-run with snakes. I didn't put a dent in the population, there. I don't know how they could get rid of that many snakes, but they sure needed to. I sure wasn't going to go for a swim, there, can tell ya that! I KNOW they're not poisonous, but hey, they're mean little critters and I didn't know that there might not be a moccasin in there with 'em somewhere.