I could be wrong on this, but i don't use slugs in my modified choke mossberg. Can you screw out the modified choke tube and use an open choke on that shotgun?
If you are looking for a deer-hunting slug slinger, consider one with a rifled barrel designed specifically for slugs, for more accuracy (with slugs, it will cast a donut with shot).
I am not personally familiar with a "reduced recoil" slug shell; maybe somebody else will speak on that.
It looks to have a removable choke tube, so you could swap it for a less restrictive tube like their spiffy-looking "tactical cylinder bore" tube.