I've got the 870 super mag. I started out with the remington super full trk choke, and got best results with 3.5in #5 federal flight controls. I decided to buy an undertaker, and it does about the same, maybe alittle less than the factory choke, but i still can kill a turkey at 45 easy. Be ready for the 3.5in shells, they kick alot more than the 3in, i don't really know why, they just do.