In my son's senior year he suffered a massive concussion in football, kid he was tackling ducked his head, they met helmet to helmet it was just one of those things that happen. The other kid staggered abut four yds back and popped back up. My kid dropped like a wing shot quail, out like a light for 15 min. Before the "hit" my son shot a lot of heavy waterfowl loads in 12 gauge as in 3 1/2" . After the "hit" he has downsized to 20 gauge. When I asked him about it he said the "big loads" hurt too much, I asked if it was the shoulder, he said no, I get headaches after two or three shots. He used to shoot my Red Hawk .41 mag, now it gives him headaches as M.D. alluded to due to the barrel cylinder gap concussion. So, I have little doubt that heavy kickers do cause physical injury, and furthermore what is defined a heavy kicker is totally the perception of the individual shooter.
You make a great case for cumulative TBI and how that can change one's sensitivity to recoil and to subsequent, even milder insults.
It does change the equation and folks have to adjust to their new tolerance level for recoil, noise, etc.
In essence it's a reset of the baseline of what's tolerable and what's not. We need to listen to our bodies...
DF
