Help me Sight In My AR-15 (Longwinded….sorry)

[NWIeng]

Okay, so here’s the problem I’m having. I have a 20” flat-top AR-15 with an NCSTARdetachable carry handle mount with the built in A2 rear sight. On the front, I have an KNS Precision extrathin front sight point, with fine ball top mounted in place of the standardfront post.

I was out at the range today with the wife and it shot greatat the 25 yard where we took it out. Thiswas expected as I had it previously zero’d for this distance with the rearsight set at the ‘Z’ mark.

To finish out the outing, I wanted to try it out at the 100yard range using some of the IMC’s we reviewed last weekend at a localAppleseed shoot. Here’s where theproblems arise…

I knew I’d have to crank the rear sight down in order to getit back centered on the 12”x12” shoot-n-see targets we had mounted. I was initially estimating the bullet hit POI+/-3” high without the rear sight adjustment, so I cranked the rear sight down12 clicks for 3 MOA. Well, long storyshort, after some not-so-useful input from my ‘spotting partner’, I eventuallyhad my shots centered after 22 CLICKS downon the rear sight. So I’m thinking, 22clicks = 5.5” of vertical movement at 100 yards. Something’s not right with the ballisticshere I think.
So I’m wondering this. Since the rear sight will do more than a whole complete turn for changein elevation, did I zero the rear sight at 25 yards in the incorrectposition? Or could that amount of clicksactually be correct? To me, somethingdoesn’t seem to be adding up?
After finally getting it zero’d on that setting, I didre-confirm that it truly was 22 clicks to bring it back to the Z setting.

Does anyone have an idea what could be going on? Another issue to leads me to believesomething is off is that the front sight top is sitting slightly higher than the front sight guard ears,which almost suggests something may be off.
I know the NCSTAR isn’t the most fabulous detachable carryhandle sight, but the adjustment clicks are very firm and audible, somis-counting the clicks is pretty difficult to do.

 

[Lancem]

Well first off the front sight needs to be lower than the ears, they are there to protect it and if it's above them, well that's not good.

As far as the 22 clicks on the rear, I'm thinking that your sight radius may be more/less than what the sight is calibrated for?

 

[phylodog]

I would suggest bringing the rear sight all the way down, then forward until the "Z" is facing out to the left. Then bring the front sight way down until the base of the post is sitting near flush with the FSB between the ears. At that point, using the front sight to adjust for elevation and the rear to adjust for windage, zero the rifle at 100 yards.

If zeroed at 100 yards and you want to shoot at 25, you should expect your POI to be approximately 2" low.

 

[Jtgarner]

I would suggest bringing the rear sight all the way down, then forward until the "Z" is facing out to the left. Then bring the front sight way down until the base of the post is sitting near flush with the FSB between the ears. At that point, using the front sight to adjust for elevation and the rear to adjust for windage, zero the rifle at 100 yards.

If zeroed at 100 yards and you want to shoot at 25, you should expect your POI to be approximately 2" low.

This!
Set the base of the front sight level with the top of the FSP like this:

Then set your rear sight to Z, but make sure it is the low Z, You can probably get it to Z with a huge gap in between the bottom of the rear sight and the carry handle. It should look like this (also make sure the windage is centered):

Like phylo said, start up close (military actually starts at 25 yards with sights set to 6/3 minus 2 clicks this should be where the Z is). Do all elevation adjustments with the front sight and all windage adjustments with the rear sight. When you have it sighted in at 25 yards don't touch the front sight again. Take it out to 200 yards and shoot it (because of the trajectory the sights should need very little adjustment).
This is how (or at least to the best of my memory) we did it in the Marine Corps when we still used irons for the range.

Edit: if this is not working, and you are still adjusting the front sight too high, you may have the wrong front sight installed for the height of your rear sight.

 

[need4speed255]

I personally don't like the standard way of zeroing the AR. If you guys haven't read the "Improved Battlesight Zero" method then I suggest you take a look at it. It makes the most sense to me.

http://www.fsguns.com/ibsz.html

There is also a revision on the above method:

RIBZ - - Revised Improved Battlesight Zero (now with down-loadable 50 yard zeroing target) - AR15.COM


Just thought I would share since it is related to your topic.

 

[need4speed255]

I got a double post due to the forum stalling. Delete if you like.

 

[sloughfoot]

Those KNS sights with the ball on top are a gimmick.

I bought them, tried them, and they are now in the bottom of the drawer.

Changing it to a standard square .072 front sight will eliminate one variable, the actual top of the front sight. I use the .072 for competition with the 20 inch AR out to 600 yards.

I can't answer about your number of clicks from 25 to 100, the question is really kind of meaningless.

I suggest you consider using jtgarner's advice on zeroing, especially the part about actually shooting at 200 yards.

 

[mvician]

Front sight is for elevation, rear sight for windage and range beyond 300 meters

BattleField Sighting