Go to Wally world and buy a box of 100 low base #8 shot. Check out You Tube or whatever and watch how to shoot a shotgun. If you stick your strong arm straight out to your side like a scarecrow and then bring your arm forward to a 45' angle you will find a pocket in your shoulder between the collarbone and front deltoid. When you mount the shotgun the toe of the stock goes right there and the comb of the stock comes up to your cheek. Tuck it in and lean slightly forward when you shoot. When you go back to heavy loads like buckshot and slugs always end the day with the #8 shot, it will help mitigate flinch.
