If you buy a slug barrel for your 870, make sure it has a cantilevered barrel. Otherwise you have to buy a harness that fits over the receiver which adds expense (about $50, I think) and is kind of a pain anyway. I think Mossberg makes a rifled barrel for an 870 (maybe others) and you may be able to do better than Rem prices. (I have a friend who has a non-rem barrel (I think Mossberg) and it works just fine).