Hey /k/, Im also new to shotguns, just got a Remington 870. I

No choke with slugs. No need, and full choke could give you some real problems. You could possibly use modified choke, but improved cylinder bore or cylinder bore (basically zero choke) are preferred.

Rifled slugs are fine in a smoothbore barrel (that's in fact what rifled slugs are made for.) Sabots are okay in a smoothbore but cost accuracy.

Sabot slugs only (not rifled) in a rifled barrel.

In some limited circumstances, you can shoot rifled slugs in a rifled barrel, but (unless your rifling and the slug are compatible and the manufacturer recommends it) you'll cause unnecessary wear to the barrel.

Rule of thumb with barrels and slugs is that one OR the other should be rifled, unless you have a well-paired rifled barrel and ammo that both manufacturers give the OK on.

>>34208318
You can shoot slugs though a choke. The little grooves on the slug itself are meant so it can squeeze through a choke; not act as "rifling"

>>34208571
Awesome, thank you anon. Takes a load off my mind. Thank you again.