FG We have the same problem right now with a 3x9x40 bushnell trophy on my nephews mossberg 500 with a cantilever slug barrel , its still shooting low at 50 yds and the adj. is maxed out. I pulled the rings and swapped them, still didnt work. Im taking it back to Cabelassunday, ithink i might get something different after hearing about another one going bad