Questions about zeroing, "mils" and adjusting AR15 aperture sights.

K

Kimio

New member
So I was at the range this past weekend trying to get my AR15 to print properly on paper at roughly 25m

One of the range masters was kind enough to help me zero my rifle, and had mentioned the translation of "mils" and the clicks of my aperture sight for windage and elevation.

My problem is that I don't truly understand how this translates for long distance shooting.

For example, I was told "x" clicks would translate at 25m for roughly half an inch? But at 300m that would shift the PoI roughly 2"-3".

I think what I'm really trying to grasp is how much each individual click on my rifles irons will move the PoI of my rounds. Is there an equation I can use to determine this? How does this apply to scopes with mil dots and how do I read such scopes? I've tried google-fu'ing things like this and unfortunately I just get even more confused reading articles and forum posts on this topic.
 
Kimio, for a standard AR-15 with the normal length barrel, etc.. if you zero your weapon for 25 meters then you will essentially be on target at 250 meters using standard military 5.56mm Ball Ammo or it's equivalent in .223 Remington.

This is because while your line of sight is direct from the iron sights to the target, the projectile must follow it's trajectory where it will first "arc" upwards through the target at 25 meters crossing your line of sight, then reach it's zenith and begin dropping, again crossing your line of sight, and would strike a target at approximately 250 meters distance.

Essentially if you are on at 25 then you'll be on at 250. The bullet is light, wind does effect it, problems with the trigger and breathing will effect it. But if you are shooting right and you are zeroed right, then you'll be on.

Here is a link to a good Army Field Manual, check out the section on zeroing procedures.
https://archive.org/stream/FM23-92006#page/n0/mode/2up
 
For the standard M16 20 inch rifle, here's what the USGI manual says on the changes per click of the rear sight:

1/8" at 25 Meters
1/2" at 100 Meters
1" at 200 meters
1 1/2" at 300 meters
2" at 400 meters
3" at 600 meters
3 1/2" at 700 meters
4" at 800 meters

For the FRONT sight, the changes per click are:

3/8" at 25 meters
1 3/8" at 100 meters
2 3/4" at 200 meters

Note that for sighting in per standard military method, you set the rear sight at 300 meters and sight in at 25 meters, making all elevation adjustments with the FRONT SIGHT. Leave the rear sight elevation set on 300 meters.

As an extra, here's some very interesting information on how to get far more use from the military rear sight.
These were developed by Colonel Sandoze USA (retired).

The Sandose Improved Battlesight Zero allows you to mechanically change the rear sight so you can lower it BELOW the 300 meter setting.
This method gives a battle sight setting that allows hits on target from any range from 0 to 230 meters by aiming at center mass. This will give hits WITHIN 2 1/2 INCHES AT ANY RANGE up to 230 meters.

The Sandose Revised Improved Battlesight Zero allows using the metric rear sight at the standard American ranges of 50, 100, and 150 YARDS, but still leaves the metric settings usable, so if you want to shoot at 400 meters you can still roll the sight to the 400 meter setting and be on target.

http://www.ar15.com/forums/t_3_18/328143_.html

I set my M4 carbine up with the Revised Improved method and it really works.
Lowering my sight 4 clicks below the 300 meter setting puts me on target at 50 yards.
Lower it 6 clicks and I'm on at 100 yards.
 
Thank you all for the information. It was very informative. I'll have to test these things out when I get back to the range.
 
You must log in or register to reply here.
Back
Top