I have a DPMS ar-15 with 16 in barrel. I mounted a Bushnell holo sight on the fixed carry handle. This weekend I tried to sight it in.
To start with I zeroed the holo sight at 25 yards. I was able to put 3 rounds touching the bulleye. I then set a target at 100 yards thinking all I would have to do is move the sight up or down to be back at center. I could not even hit paper  at 100 yards. So I then moved to 50 yards. At 50 yards the I was hitting 12 inches above the center of the target. I then shot again at 25 yards and could hit center of target.
I am shooting blackhills ammo.
Any idea why I am so far off from target at 100 yards or 50 yards?

no ideas anyone??

My friend and I have sighted in many scopes. I was at my friends house and he has a 25yd-300 yd range set up at his house in the country. We could not figure out why we could be so far off, should of been just inches off at 100 yards. Even sighting it in at 50 or 100 yards I don't think that it will make much of a difference as it will still be way off if I try shooting less or more yards other than what I have it zeroed at. I think I will give the guys at CMMG a call. They are about 25 minutes from where I live. Surely they have ran into this problem before or may know the reason why it is off so much.

Thanks for the reply back