ORIGINAL: Paul L Mohr
If you are looking for distance and accuracy you are going to have to pretty much get a rifled barrel with a cantilever mount and some optics. And then you are still only talking about 100 yards, maybe a bit more. Then you are going to have to spend some money on different loads to see what works best in your gun. It gets expensive FAST.
I would honestly stay away from the the really high tech super fast offerings that say they can shoot out to 200 yards. They look good on paper, but I haven't seen or heard of too many guns that shoot them that well. Most of the barrels you will get for an 870 just don't seem to shoot those fast light loads that well. Some do though if you want to give them a try. I wouldn't get your hopes up though. Most have good luck with bullets in the 400 grn and up range at speeds below 1700 fps.
In my honest opinion if you are looking for range and accuracy a quality Inline muzzle loader is the way to go. I own both and the ML is a bit more of a pain to shoot, but it is easier and cheaper to work up a good load for.
Paul
I shot 2 1/2 inch groups at 125 yards with a red dot with the hornady's, they can def. reach out. My neighbor was shooting 3 inch groups at 150 yards with lightfield hybreds. I'm not saying your wrong just giving personal experiences with those hornadys.