you could also look into escort shotguns? They make a slug gun that is semi auto, fully rifled and has a cantillever scope mount on it. I believe the price was under $300
I have harvested many with the 500 I bought 19 years ago. It is a super gun for the $$. Usually you can get one like I bought my son with 2 barrels one for birds and one for deer. They are very accurate. The 870 seems to have a little better fit and finish so it would depend on the $$ difference I guess. If I could find a .357 or .44 lever action for a decent price I would snag one of those for my arsenal too. All those seem to be pretty high right now though. Good luck to you