My HD 870 wears the 20" rifle sighted barrel and a +3 extender. The Barrel has the screw in chokes and when I Deer hunt in Shotgun only areas its my go to gun(Minus the extender). The barrel comes with 4 tubes: IC, Mod, Full and rifled. The rifled tube does good with Sabot slugs and the sights allow precision shooting with the slugs. I have a 28" screw in choke barrel also and I used the gun for birds, so it is a 3 way gun; Birds, HD, Deer.
My 3 gun Shotty is a REM 1100 mock up of a Comp master and I would not use it for HD. Its too long and heavy but it rocks in 3 gun comp
9 rounds as fast as you can pull the trigger and aim