Nice looking 870 and not a bad deal either.
I like 500's but in a rifled barrel I think the remington is a bit better even though Mossberg was the first company to sell rifled shotgun barrels, they have a slow twist which is not that great with modern sabots.
Some slug guns are very accurate, My BPS was 1" @ 100yds with winchester supreme Partitions. it would only shoot the 3" Mags this good as the 2-3/4" were all over the place. I took a Ranged 285 yd shot on a deer and it was a complete pass thru with a LOT of damage to the shoulder and internals. I have a mil-dot scope on it and had a lot of practice with this gun at various ranges so I knew where it would hit at any range out to 300 yds. It was not my intention to shoot that far but I hunt bean fields in a shotgun only zone so 150 yd shots are common. this deer just irritated me, He walked into my sons stand about 15 min after he walked up to my stand because he was "bored" it was a slight down hill shot and he went about 20 yds and dropped. It was interesting as I shot and then just a second later we heard it hit.
Point being is that you can get a barrel, scope, ammo combination to shoot good at longer distance than once possible. My SBE was shooting under an inch @ 100 yds with the shaw barrel, I sold that gun because I wanted the Camo Version (yea, I know I could have had it dipped) and the new one will not shoot under 2" with any ammo I can buy. I also sold the BPS just because I had the SBE/shaw combo and I do not like pumps so I really screwed myself over this time. Looking at a TC Pro Hunter to replace the SBE Slug Barrel.
If that does not Work I am buying another BPS...