If it is of any comfort, I have not heard of any bad H&R slug guns. I have an Ultra Slug 20 the big heavy. She is a shooter. I know of one older tracker slug gun that out shoots mine. I would say you find the ammo it likes and you will be good to go.
By the way, it is a GrayBeard rule if you buy a new gun you have to show pics
Congrats
Lonny