When I sight in slug guns I either use a Lead Sled with 25 pounds of shot in the tray or I drape a padded gun case over my shoulder. Either helps a lot. I also find it's easier to shoot hard-kicking guns if they have good, light triggers like the Savage Accu-Trigger. Wearing lots of hearing protection -- ear muffs over plugs -- helps, too. A lot of what we perceive as "kick" is the noise of a muzzle blast. As a shotgun shooter, I always notice how loud centerfires are when I'm around them.