AR15 100 yard zero

[repo]

I have a 16" AR. I zeroed it at 25 yards on the "Z" notch, then clicked it back to "6/3". It is spot on at 25 yards but a couple inches high at 50 yards and completely above the paper target at 100 yards.

I plan to shoot mostly at the 100 yard berm so what setting do I click the elevation to for 100 yards? It only has marking for 400 and 500 and 6/3. On 6/3 it is already wound all the way down. I want to keep the "battle zero" but be able to click it for 100 yards.

 

[Onmilo]

Use the small apeture.
Zero the 6/3 setting one inch low at 25 meters, not yards, using the front sight to adjust the height.
If you have to course adjust the rear sight to gain zero, count the clicks, go back to the 6/3 setting and loosen the elevation wheel lock screw with a 1/16" allen wrench.
Pull up on the elevation setting wheel and turn the bottom adjusting wheel the number of clicks in the direction you went to set your zero.
Push the setting wheel down and retighten the lock screw.
Depending on the ammunition you are using, you should hit about one inch high using a point blank front sight picture.HTH

 

[John4me05]

If i remember correctly for military spec the Z was battle sight zero shot at a range of 32 or 36 yds.... Then the 3/6 was supposed to be close on 300 and 600....

 

[Blackfork]

What sight picture?

Are you shooting at a bullseye target or something else? Are you shooting point of aim/point of impact or a six oclock hold?

Most folks shooting six oclock at bullseye will have a different zero than point of aim or center mass.

 

[repo]

Yes I'm shooting at a bullseye with six oclock hold. I just found a couple articles on zeroing for this kind of range, "improved battle sight zero" and "law enforcement zero". I guess I will have to experiment a bit.

 

[Jenrick]

First off for the sighting system to work correctly you need to use the large aperture to zero. If I recall correctly the Z is for zeroing at 36 yards/30 meters. The zeroing target has a 2"ish square (I think it's actually 5cm or something) with a 1 cm dot about 3-4cm below it. Aim at the center of the square, and your rounds should impact the circle when properly zeroed. Go the one click up to 6/3.

Now out to 300yds using the large aperture your rounds will strike on the torso of a standard military target. Once you get to 300 yds flip to the small aperture, and rotate you're elevation drum as needed at 400, 500, and 600.

-Jenrick

 

[W.E.G.]

Trying to rely on those numbers printed on the wheel is not the best practice.
Better to learn the value of the clicks so you can really understand your zero.

Each elevation click of a standard A2 sight moves point of impact 1.375" at 100 yards.
That's 1.375 MOA movement per elelvation click.
That's quite a bit of movement for one click.
Quite disappointing for target-shooting too if you ask me. Too coarse.
But, it is what it is, so learn it, or get a National Match sight with finer threads.

Each windage click of a standard A2 sight moves point of impact 0.5" at 100 yards. That's 0.5 MOA movement per windage click.

Right out of the AR15 manual


Its a good idea to mark your sight knobs with a bit of paint so you can keep up with where the knob is positioned - especially the windage knob - but I use paint on the elevation knob too. You can mark the elevation knob for specific distances, with specific ammo, and you can stop guessing/hoping that the standard marks on the wheel have any specific relevance to your objectives.

 

[W.E.G.]

AR15 sights are 2.6" above the bore.

With 55 grain ammo, you are going to be 6.3" high at 100 yards if you are "spot-on" at 25 yards.

I hope this chart sheds some light on what is going on with your bullet trajectory if you zero your AR15 to be "spot on" at 25 yards.

That bullet is going to strike above your point of aim for a long way if you zero for 25 yards.



By comparison, if you zero for 100 yards, you will be "spot on" at 100 yards, and never more than a little bit low at shorter ranges, and still only a little bit low all the way out to about 250 yards.

 

[P-32]

I think you are tying to make things too hard.....why not just write down the number of clicks you need to hit the 10 ring.

I have the dope on the back of my clipboard for each of my M-1's and AR's from 100 to 600 yards depending on what rifle it is. The clip board holds my score book. And yes, I have used the wrong dope. I normally figure this out at the first sighting shot.

 

[ma96782]

Here is another way to do things...........

http://groups.msn.com/TheMarylandAR15ShootersSite/improvedbattlesightzero.msnw

Aloha, Mark

 

[jpwilly]

MA thanks for the link...