Get yourself a shotgun or muzzle loaderwith aniron sight, put out a bullseye target at 100yds, shoot at it without a rest (off hand) and report back with your results.
Now you go adding "off-hand" in there....lol. Guys..I'm watching the "You make the shot" segment, yesterday (TV hunting show)....and they discussed this very thing. The hunter had a rest. He was using a ML, iron sights.....and they said the 100yd shot wasn't that big of a deal. I don't know???? Don't care! Just figured they knew what they were taliking about.
I asked if the question was fair. I think it was.