I just got back from zeroing with slugs (at 50 yards), and noticed that the rear signt had to be adjusted almost all the way up (aligned with the top mark on the side) for elevation.  In the beginning, I was outright missing the entire target board by about 24" below the point of aim.

Nothing seems "wrong" with the gun, but since the ghost ring sights were designed specifically for this gun by Mossberg, I was wondering if any other 590 owners also have the rear sight adjusted the same way?  

I haven't sighted mine at 50yds yet, but at 25yds I didn't even have to adjust the sights at all.  Seems strange?  I guess I'll have to go and sight mine in at 50yds and see what happens??

Sorry joe_c (nice Kid Rock ref.), I sighted mine in about a yr ago and dont remember.

What I do know - it is one ragged hole at 50 yards.

How did yours come out?