I had a Knoxx Spec Op on a 12 gauge 870 SM years ago. The recoil into my face was terrible and that was using 3" magnum shells, NOT 3 1/2". It was drawing blood on my cheek after 3 rounds at the pattern board. I sold the gun to a 24-year-old co-worker who loves it. I now have an 870 SM with the original wooden thumbhole Monte Carlo stock with roll over cheekpiece. It does not smack my cheek like the Knoxx Spec Op did. I still only use 3" shells tho.