You’re talking about flinch, and snipers have it already, a shotgun requires no aiming skill, so a flinch on it would do nothing, the best way to do what you are asking is to decrease the speed you can draw a shotgun to a firing position from sprinting or sliding while being shot. Although i must say that nerfing shotguns in this way doesn’t make logical sense as it would make them useful only as a corner clearing gun and make it’s pve utility a lot less. In my opinion, sidearms and submachineguns should be the de-facto counter for shotgunners, they should be buffed to counter sprinting shotgunners, but it’s a delicate balance.