Doyle....
I've two "Serious" 870s I use for HD and hunting. One has an 18" chokeless barrel, the other a Remchoked 20" barrel with a rifled tube when I slug hunt.
Otherwise, both are set up the same with peeps, mag extensions and great triggers..
Benched, the tubed one is about an inch tighter at 100 yards.
That's with KO Brenekkes.YMMV.
BTW, both groups showed a bit of keyholing,even though they were excellent otherwise. The tighter one showed less.