Late November 2012, I bought a new M&P-15 MOE from Bud's Gun Shop. I did not take the time to shoot it until a couple of months ago. The MOE style is not the current style, but still has MBUS rear sight and A2 front sight. I am trying to sight in the rifle, but have run into a problem on the vertical height adjustment. At about 25 FEET, the POI was about 4 inches low. I learned how to adjust the front sight post, and after two more range visits, I have bottomed out the post in the sight, but the POI is still about 2 inches low.

After checking around the forums, I see that there are two different A2 sights, the normal, and the F stamped. Turns out I have an F stamped sight on the front. What can I do to adjust so that I can zero the sights? Any suggestions are appreciated. I'm not keen on replacing the entire front sight.

You should start your zero point at 25 yards then 50, then 100.

You are most likely to close to the target. The sights sit about 2 inches above the centerline of the bore, so at that distance your point of impact is going to be lower than your point of aim.

Initial sight in should be at 25 yards, with actual shooting to confirm point of impact at 100 yards. Check your trajectory tables. The 5.56/.223 would normally be sighted so that, at 25 yards, it is hitting two inches low (that is an illustration, not an actual measurement), and only then is it "on" at 100 yards.

Like the others have said, sighting in at 25 feet, you are going to shoot low. That's under 10 yards which is a fine distance for pistols or throwing rocks. Look at some of the AR-15 trajectory charts and you'll see why your POI is where it is.

LOL That really made me laugh. Thanks.

I sighted mine in at 50 yards with the irons.

Like everyone says 25 feet is way to close.

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AR15Sport Shield9 642/38 15/22

Like others have said, unless your rifle says Daisy on the side, 25 ft is too close. Get an initial sight in at 25 yards if you are new to shooting. Once you can group consistently at that distance, you can decide what type of zero you would like to set up.

If you follow the military method, you must zero at 25 meters (not yards). At 25 meters, your point of impact should be about 2 centimeters lower than your point of aim. Once this zero is achieved, your point of impact and point of aim should be the same at 250 meters (using the long range aperture). If you zero using yards as your measurement, your zero target will be about 85 inches closer than at 25 meters, so your point of aim and point of impact will be about 70.8 feet closer or about 179 yards (since yards are 36 inches and meters are 39.4 inches, the additional 3.4 inches account for the difference). Using standard 55 gr. 5.56 ammo, should put your bullet strikes progressively higher at 50, 100, 150, and 200 meters, finally returning to POA at 250, and slightly lower at 300 meters. I could be wrong, but this formula worked for me for about 21 years. Your current sight set-up should work fine for this.

Good Luck and good shooting.

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SFC, US Army, Retired

There is a reason the AR's are not called short guns. When I was in the Marine Corps we shot with iron sights at 500 meters. this rifle is not designed for 25 feet, 6 meters.

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Retired Marine Gunny

Thanks all for the good information. I have been thinking self defense pistol for the past 5 years, and did not even consider trajectory or iron sight height relationship to bore axis with the rifle. Thanks again!

Download this target and take it to the range with you next time you go. If your range is like mine, it is marked in yards, not meters, so if you want to go with the 25 / 300 meter zero, you will have to do the math.

http://www.bobdbob.com/~deneb/doc/ta...rbine-zero.pdf

I sighted mine in at 25 yards, then moved it back to 50 yards and sighted it in. With a 50 yard sight in, you are on at 50y and again around 200y, and only a couple of inches high max anywhere in between. That covers any shot I would take hunting or self defense.