I have a new 835 ported 26" 12ga. When patterning it for the first time I put an undertaker (for lead) choke in it and shot Fed. #5 3" mags. Here is my dilemna,

at 10 yards it shot a hole clear through the target but at say 25-30 yards it is 6" to 8" left of target and actually off of the 8 1/2 by 11 sheet of paper (turkey head) completely.

Is this common from this set up? Does one normally have to move off of the bird?

I have one fiber optic front bead and no rear adjustable sight. Would this make a difference?

I will try a different combination tomorrow. I appreciate your thoughts.