AR/M4 sighting question


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Matthew_Q
May 15, 2003, 10:29 AM
So, I built a 16" A4 with CAR length handguards. I put an Armalite detachable carry handle on top. I did the adjustment to the rear sight, so that when it's at the 8/3 setting, it will go down four full clicks before bottoming out.

First shooting, with the small aperture, the POI was about 12-13" high at 50 yards. I could not adjust the front sight at the time, so I cranked it UP about 1.5 revolutions to lower the POI...

Anyway, I'm not completely sighted in, but I have a question. I know how to sight in and get it all good, but I have specific usage applications, and want to know what different I need to do.

I built the rifle for use in Tactical Carbine matches. They are run like IDPA matches, but with rifles. Ranges are usually no more than 25 yards, with occasional stages out to 50 yards. This will mean I'll be using the large aperture of the rear sight.

I shot in a match this past weekend, and noticed most of my shots were several inches lower than where I was trying to aim. Yes, I know about the 2-3" holdover to compensate for the sight's height over bore. POI was probably 6" low from the POA.

Given I'm going to be using the large aperture at ranges usually within 25 yards, but occasionally beyond, does anyone have good suggestions on how to sight in for this range? Should I set the rear sight at the 8/3 setting, and adjust the front post to get POA at 25 yards? How will that affect POI at closer and further ranges. How will that zero affect the small aperture at different ranges?

Input is greatly appreciated!

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Onslaught
May 15, 2003, 11:12 AM
Everything I ever wanted to know about zeroing an AR came from here:

http://groups.msn.com/TheMarylandAR15ShootersSite/zeroingmethods.msnw?pgmarket=en-us

Good luck

444
May 15, 2003, 11:35 AM
I am not sure I understand your problem. When zeroing, the elevation adjustments are made with the front sight. You can adjust the front sight with the nose of a round of ammo.

Matthew_Q
May 15, 2003, 11:56 AM
What I'm getting at is...


What's the best zero for close range stuff like I mentioned?

If I zero using the large aperture at 25 yards, what will the affect on the POI be at closer, and at longer ranges?

Given said zero, how will this affect the zero with the small aperture?

444
May 15, 2003, 12:34 PM
I realize that you are using your carbine for a very specific purpose. However, if it was me, I would simply use the improved battlesight zero as shown on that link posted above for the Maryland AR Shooters group.
You have a 50 yard zero using the improved battlesight zero (IBZ).
You then fire your rifle at closer ranges to see where it hits.
You will find that at it's most extreme point, it will be about 1 1/2 low. So, to make a head shot in the little boxes that come on most cardboard silhouettes, you aim right in the center of the forehead (not in the center of the head).
The reason I would go for this standard zero is because then your rifle will be properly zeroed for all purposes, both recreational and social. By using your rifle to compete, you will become a master at placing your shots with precision using a standard zero. This is similar to the various carbine classes I have taken. You zero your rifle at the range that is most advantageous to the cartridge/rifle combination. Then you fire it extensively at all ranges to become familiar with exactly where it hits. The classes I have taken fire from 3 yards out to 400 using the IBZ. With very little practice, you know right where to hold to place the bullet right where you want it.
Put another way, you have to zero at some distance. At other distances, this will be a comprimise no matter where you zeroed. So why not use a zero that will be the optimim for your rifle ?

The best way to determine where your rifle hits with the different apperatures and different distances is to simply fire your rifle and see for yourself. Different loads, different barrel lengths, different height above bore of different sights and carry handles will make a difinititive answer impossible. But you can find out right where your own rifle hits by simply trying it.

Jeff White
May 15, 2003, 02:17 PM
I'm going to add my recommendation for the Santose IBZ. You will still have to hold over to compensate for the height of the sights above the bore on close range targets in your matches anyway.

444 is right in that it doesn't take much practice to learn where to hold at close range. I doubt you'll be able to adjust the iron sights so they are dead on at 3-15 yards and still be able to hit at 50.

Jeff

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