Personally, for myself, I'm only good to about 600 on deer with my 243AI and a 105 Amax, given little wind. I don't shoot enough past 600 to be confident in my placement.
Farthest I've killed a deer with that one (that I know of for certain verified with a LRF that is) was at 494 yards. That one was a rather large muley, that took one from the last rib and exited in front of the off shoulder, and since the shooting is the fun part, when he managed to slowly get mostly back to his feet I shot him again through both shoulders. That one took about 2" of leg bone with it out through the hide on the off side.
I think that I likely did kill some deer a bit farther out than that as a youth, given the holds that I was told to use by my dad when I started out with a 6mm Remington though.
