I have one in my 835 and love it has a good tight pattern. The guys that have in a mossberg 835, what is the constriction of the choke you have and what kind of shells are you using?
I got them on my Benelli guns, they have been in the booth beside me for the past 3 years at show, great guys. Knight & Hale use them, too, and they are not being paid to use them. The best round is the Heavy Shot 13, in 6 shot, it has been winning most all of the contests for the past 4-5 years