I've taken a couple of deer at 100yds with a .30-30 shooting offhand but have never taken a shot at any deer with a muzzleloader, shooting offhand.
Have always been seated in a tree stand or on the ground...and would take a 100yd shot that way without hesitation, it's nearly as rock solid as bench shooting, I've practice it at 100yds, know I can do it easily, etc.
But offhand standing I'm not that good...I'm still learning / developing offhand standing shooting skills...intend it to be my primary weekend practice this year. Last weekend I put 50 shots in a 3" circle but it was only a mere 25yds away.....yesterday, I put 50 shots in a 5" circle at 40yds...but that would be 10" at 80yds which is no good.
At typical 40-50yd woods distances, I'd shoot a deer offhand with confidence that I'd take him but I'm not good enough yet to try anything beyond that...so the next step is to shoot at 50yds until I hit 100%, then move it out 60yds until I can hit it 100%, etc...may take all year to get 100% at 60yds, but it'll be a good reason to practice. :grin: