My son & I both use a Mossberg 500. I've had mine for 10yrs now. If your not using a xx-full extended choke they won't pattern well. My setup is as follows 12ga 500 w/ mossbergs xx-full extended choke, Nitro 4x5x71/2 shot load. I easily get 35 pellets in head & neck @40yds. My son's setup is 12ga. 500 w/ Undertaker xx-full extended choke, and same Nitro load. His gun gets about the same in head & neck.