Presently 247 yards. That's how far I can shoot from my front porch. I've never shot a deer from my front porch as I have a thing about shooting "yard" deer that have been hanging around all summer. However, I know exactly how much of my scope plex a deer's chest takes up from watching the yard deer.
When I still hunted out west, my max was a bit further but not much. My longest shot ever was 387 long steps -checked twice- to an antelope that I shot with a .280 and a 140gr NP bullet. It was dead calm and I was using a bi-pod. Using the plex of my scope, I had ranged him at 400 yards.

I'm not sure. Once after the trigger broke on my #1 Bob, I started sharpening my knife like my friend Wolfer showed me over in the Small Game Fourm. I kept one eye on the blade, another on my quarry. Ran out of steel before the bullet ran out of yards. Sorry to say, I had no witnesses.