I've shot some big stuff, to the point were I'd get a head ache after a round of two. The only thing that ever hurt was a 3" Turkey load in a very light single shot. It was my fault , I was walking in from Turkey hunting.The one abandoned silo on the farm was a great spot for pigeons. The silos have that square hole about 3 feet off the ground, about 2.5x2.5 feet. There was only half of the roof on top, and stupid me I reached through the hole bent over and twisted my body to shoot straight up.
All I can say is that it hurt and I sat there for a good 5 minutes with the worst back pain I ever had. Then had to crawl in and get the to birds I shot.