I must be incredibly stupid but ...
I have a M15A4 w/ bolt on front and rear sights . I zeroed as taught at 25m with the 300-600 aperture resulting in 1" group. At 100m impact is about 1 foot high w/either aperture and the rear sight bottomed out and front sight base even w/top of its well , just like you're
supposed to . Raising rear sight el. up to eight clicks does'nt move impact noticeably . This is killing me cuz I know from the 25m results thgun is shooting correctly . Any help would be appreciated !!!