i am sorry for not being clearer about the buckshot/slug and birdshaot together. as far as i know you can have buck, slug and bird ammo in your HD shotgun.
what i didn't type earlier i apologize for any misunderstanding and confusion, was that the NJ fish and game regs. state that you can't carry ammo like that. heres an example if i were out hunting deer and small game was or wasn't in seaon. like rabbits or squirrels i can't have buckshot and or slugs in my gun or on my person and also have even 1 round of birdshot too. you can only carry ammo specifically for what you are hunting. meaning deer buckshot #4-000 and slugs only and if you are out waterfowl hunting no larger than T size steel shot , so you don't want to get caught with even 1 lead shot shotshell. its a 20.00 fine per shell for that. also meaning that i can't carry buckshot for deer and a few rounds of steel shot if i should come across a lake that maybe has a few geese or ducks within range or not.