How far would I feel comfortable?
For fun, I shoot the 200yd gong at the rifle range, offhand. One handed, 7.5" barrel .45 Colt 250gr@1100fps. And I hit, often.
For game? Big game, half that, and rested if possible.
Small game? half that again, and wishing for a .22 instead of a .45
Shooting something like a scoped Contender? rested, in .222 or .30-30, or .45-70, my "comfortable" distance will be a bit different.