Shooting slugs and buck shot in 16 ga 870 Express

[dieNusse1]

Choke tubes are available for turkey shooting and I seem to remember ones available for slugs. I guess you could shoot sans any tube but that may bugger the threads. (???)

[Virginian]

You can shoot slugs and buckshot WITH the choke tubes. As noted, shooting without a choke tube is definitely not recommended. READ the owner's manual.

[Synchronizor]

You shouldn't have a problem with buckshot, and slugs can generally be fired through most chokes, though repeated use of slugs in overly-tight chokes can be hard on the gun. When in doubt, look for recommendations from Remington and the ammo manufacturer.

Like Virginian said, if your barrel is threaded for interchangeable choke tubes, never fire the gun without a tube installed. If you want a lighter constriction, buy another tube, it'll cost a lot less than replacing the barrel.