Dumb of the day...

Optic on straight? barrel aligned properly? Upper rail straight?
I'm assuming it's your optic is mounted to the receiver not out on the hand guard.

Does the barrel align when looking from the back and above the optic?

Also adjusting the correct direction( don't laugh, I've seen that happen a surprising amount of times, especially with dots that adjust the opposite direction.)?


Doh, I should have asked. Can you not get it adjust vertically or horizontally?

If the scope and mounts are tight, then...

Bore sight the optic with the upper off the lower and BCG out of the upper.

To bore sight get a firm position on a shooting bench aimed at a paper at 25 yards, with the upper receiver steady look through the bore and center the bore on the target's bullseye. Now without moving the upper raise your head to look through the scope and see what direction you need to move the cross hairs to get them onto bullseye. Recheck several times between looking through the bore and the optic, while making the needed adjustments until they match. Now shoot and find that it is bore sighted and make any fine adjustments based on POI.

Just because the optic was "smack on" on your 5.56 doesn't mean squat when moving it to a completely different upper and caliber.

drmajor said:

Now I cannot get it to sight in....not even near paper..

Click to expand...

Uuuuuhh.... how far away was... "paper" ?

Anytime I change optics it's first shot at 25
(hard to miss a whole target backer)

From there you have enough info that you can almost always adjust for 2nd shot out at 100.

MEHavey said:

Anytime I change optics it's first shot at 25
(hard to miss a whole target backer)

Click to expand...

This is so true, but on a new rifles 30 yds I missed my 14" x 22" target shot right over top so at least 11 high and 6.5 left. Found paper at 15 yds 11 high and 6.5 left.

I fired 2 shots and missed both.

Take the BCG out, set it on something solid and center an object in the bore down range.



Now move the optic POA to the same object.



That should get you “on paper” and now that you have something stable to fire from you can dial to the center with a shot.

Winchester.com has a nice sight computer. The standard above bore center is 1.5 inches. Example: measure what yours is and add the difference to targeting choice. A standard stand off for 308 to shoot fair to same up to 300 yards is +3 at 50 yards. Stand off on AR 2.325 add 1.125 so +4,125 at 50 yards. Per the computer per stand off shooting for trajectory.

Luckily it's pretty easy to bore sight an AR. I normally go with 50 yards, but 25 works too. Just don't go too short with the distance!

The first time I bore sighted an AR I was in my basement. I thought I was being smart because I had it locked into a vise so it couldn't move. I put a small piece of masking tape on the window 7 yards away and aligned the scope with the bore, and headed to the range. My local rifle range starts at 50 yards and we aren't allowed to put up makeshift targets at shorter distances, so instead of starting there I went to one of our pistol bays that allows rifles. There was a target set at 7 yards, so I fired a shot and hit dead center. An older gentleman sighting in a shotgun didn't believe I was dead on after bore-sighting, so he demanded I shoot a 2nd round, which also hit dead center. Thinking I had things good, I went off to the rifle range and set a 16" x 22" target at 50 yards. And I missed. And I missed again. I threw several shots downrange, aiming at various squares on the target and never once saw an impact. Frustrated, I decided to bore sight again at 50 yards. This time I was within 2" of the target on the first shot.

Being so new to AR's at the time, I just didn't realize how much those high sights change the point of impact at various distances. After that 7 yard zero I was probably shooting 16" high at 50 yards, so even aiming near the bottom of the target my shots were hitting just above it.