The funny thing about that is the 82/107's don't have that much felt recoil, between the muzzle brake and the recoil springs, it's more of a big push. I'm sure the shooter went to bed unaffected by the recoil.
I'm always amazed when people are afraid to shoot my AR-50, even after I explain to them that there's basically no recoil. The one that I remember the best was this guy that was at least 6 feet tall and weighed about 350 pounds, guy was just terrified! Even after he saw a 10 year old girl shoot it and she probably weighed 40 pounds. I told him he could shoot it for free, I would talk him through shooting it, stand behind him to keep him from falling down...
Guy still would not get behind my rifle and all the while we're talking, other people were shooting my .50! Other kids, women... he was just so scared and no matter what other shooters said, wasn't happening. Whatever, I just laughed and went back to shooting, told him if he changed his mind that he could come back and shoot it.