About 25 years I got a used M870 12 ga. , it came with 2 extra barrels. It is a 1980's shotgun.
Later on, when I was interested Trap shooting, got a 30" full choke barrel. Over the years
I have shot nearly any shell marked 12 ga and 2-3/4" without a problem. Lead, steel, anything.
Back in the day a man could get a box of low brass 8 or 9 shot for $2 and I fired tons of it.
The Rem 870 Wingmaster is a winner.
You got a great gun.