I know the problem. I have fixed several 835 and 535's like this. The factory rear sight on ALL mossbergs 835 and 535 are set on the flat plane of the bbl vent rib. The objective of a rear adjustable sight is to move your poi up or down, most front sights are stationary. I had a buddy bring me his 535 tactical several yrs ago shooting 10-12" high, after adjusting the rear sight as far down as it would (which lowers poi) it still shot 10" high. I studied it real hard and on observing the vent rib, I noticed that if you slid the rear sight back, it would slide down as the rib got lower as it got closer to the shooter. TRUST me, i have since fixed MULTIPLE Mossberg high shooting problems with this. It is an easy fix, alot of people think the sights are no good, and cant be adjusted, but it is merely an act of sliding them back an inch or two to lower rear sight enough to bring the poi down. PLEASE, before you spend the $$, go and tryt what I am saying with some bird shot and see if it works...