I have several--the one I admire the most is my Standard 870 from Wilson Combat with Vang Comp mods. My most recent is the Mossberg SPX Semi-Auto--really affordable and all the bells and whistles for a PD shotgun.
Your problem can be solved by putting a rifled barrel on that Mossy--I did this on my 590A1 and turned it into a slugster. Ofcourse you will have to replace that bead sight with rifle sights, or Ghost rings-- overall not a very big job.
Enjoy.
