Those wussy 7mm Rem. Mags.
I've only shot about three rounds through my BIL's gun and whew it moved me.
H ehadn't shot it yet and was leary of it....no kidding. I fired the three rounds, got my shoulder rotated back into place when he asked me "how was it it"? I replied "Sweet"! and handed the rifle over to him. His first round, he looked at me after it went down-range with a look that was hilarious, at least to me.
Seriously, the butt plate on our Remingtons suck. I recently bought a slip-on butt pad called Limbsaver for my "new" 12 guage and I like it. You might check it out.