M14 Forum

82nd ABN

I have never had to zero 1/4x1/4 NM rear sights. I built a preban NM upper early last year but only took it to the range once. I need to find a preban lower for it to stay out of jail in NY. So last week I sent a post ban Krieger HBAR to Compass Lake Engineering for them to assemble into another upper I can actually use. The search continues for a preban lower if anyone knows where I can find one. All I did to zero that rifle was to come up 360 degrees on the front sight post and it was shooting x's consistently off bags at 100 yards. I took the CLE rifle to the range today to zero. I only had one glitch and it has no reflection on Compass Lake. I installed an A1 butt stock on the lower and the spring must have be pretty old because when I pressed the bolt release button, the bolt would move about a half inch and stop. I figured it was the spring and confirmed it when I got home. I installed a new spring and it works fine.
The problem I have is I have no idea how to use the numbers on the NM rear sight. It has 0-5-10-15-20. Now I can assume that they don't stand for meters or yards. I think and please correct me if I am wrong, they are just numbers on the dial to give you a reference of how many clicks are in on the dial.
Another couple of question if I may. I set the rear sight up in the center and the elevation was indicating 0. I adjusted the front sight post to get me in the black. I then had to use the elevation dial in order to fine tune the zero.
Considering I will be shooting this rifle in matches, should I set the front sight post up to give me a zero at 200 yards? This only makes sense considering 200 yards is where the matches start.
I also was wondering if my assumption on the numbers on the elevation dial are simply for reference, I should leave the rear sight on 0 and adjust the front sight post to get me in the x ring, with me so far? The POI changes quite a bit when you rotate the post 180 or 360 degrees. At 100 yards, i could not get it to center, I was either a little high or a little low.
So here is the question. Should I set it up as close as possible and file the top of the sight to get me in the x ring while still maintaining the elevation dial on 0? I hope that comes across clear. In other words, set it up at 200 yards with the rear sight centered and the elevation on zero and adjust and file the front sight to get me to the x ring.
As most of you know I send these uppers out to have then built. There is a very simple explanation. The two companies I have utilized so far are White Oak Arms and Compass Lake Engineering. They provide a service that I am not capable of doing at home. Some may have heard me mention this before. They each machine flats on the barrel where set screws that are drilled and tapped on the front sight base seat against. CLE uses four screws, two on each side whereas WOA used two. CLE method is far superior than WOA's using only two screws, well three if you count the one on the bottom. Here is why it is superior, to align the front sight base you simple loosen the screws on the opposite side where the bullet was impacting. Say for example you are shooting left, well you loosen the two screws on the right side of the FSB and tighten the two on the left side hence moving the FS post to the left. I can't do this with the WOA two screw method. First of all they are to high on the outside diameter of the section that rides over the barrel which forces you to have to loosen and tap and hope you did not go to far. At least that is what my experiences has been.
CLE method is so smooth, you only loosen the screws a fraction of a turn and tighten the other side uniformly and the front sight base moved and you can hardly see it. Just an observation.
So if anyone can give me some insight on the numbers on the dial and my idea on how to zero by filing and keeping the elevation dial on zero would be greatly appreciated.
Spelling doesn't count in this post. I could not sleep last night and I have been up for approx 22 hours at the time of this post. Thanks in advance, I know I have had a lot of questions lately.

art7

OK, here is what you do:

1. The numbers are just a reference. For CLE I forget, there are either 24 or 25 clicks to a revloution. If you shoot in matches, usually all you work in in MOA or clicks, not meters or yards. Also, with a 1/4MOA drum, you will likely do 2+ revolutions to get from 200 to 600 yds so if you did have meter markings, it would get all confusing.
2. I like to start at hard zero, ie screw it all the way down till it stops, then come back up about 6 or 8 clicks.
3. Zero as best you can at 200 using the front post. One revolution of the front post is 5 MOA, so each 90 degrees is 1.25 MOA.
4. Once you get it as close as you can, lock the front post in place - CLE adds an inverted set screw under the front post. You have to invert a small allen wrench to stick it up inside the threaded hole. You want to snug this against the front post so it stays solid in place. BTW, you did remember to loosen this before we adjusted the front post, didn't you?
5. You should be within 1/2 to 3/4MOA at this point. Finish zeroing using the 1/4MOA drum on the back sight to get it on target. Rotate the rear sight slowly down to hard zero and count clicks till when you stop. Don't forget that number. That many clicks up from dead bottom is your 200 yard zero. Let's pretend you decide that number is 7 clicks up from mechanical zero.
6. Step #6 and on is optional. Count how many clicks you need to rotate the drum to get to where the number zero is lined up on the side of the sight where you want it.

You can disengage the bottom half of the drum and rotate it to bring the number 0 in line while you are at your 200 yard zero, then lock it in place. My memory is a little hazy, but if you look on the top of the sight, just in front of the flip aperture, there is a small hole that goes down through the carry handle and lines up just inside the top edge of the elevation drum. If you put an allen wrench down there, it will engage in a small set screw in the top of the elevation drum. Obviously, you first have to turn your elevation drum so the allen screw lines up with the bottom of this hole, and here is where memory fails. I don't remember if you can look in the side into the gap between the drum and the carry handle and see the set screw, or if you just have to rotate the drum 1 click at a time and try and see if the allen wrench engages. Anyhow, loosen the allen screw, and at some point, on the elevation drum the top row of knurling with the reference numbers can turn versus the bottom row of knurling. Retighten the allen set screw to lock them back together. You'll have to fool to figure out how far you want to turn it.
7. Go back all the way down to hard zero, and come back up by 7 clicks and see if the 0 lines up. Like I said, you might have to fool and try it several times till it is registered correctly.

Good luck,

Art

NoExpert

Well at least I was right about the markings.

82nd ABN

Yes you were and I didn't have to throw you under the bus!!!

Art step six is where I got confused at the range today. I realize exactly what you are saying but lets say I have the rear sight elevation dialed in. Now in order to get that set screw lined up I have to move the rear sight which will intern change my zero. Lets just say for argument sake that I am at 10 clicks up from bottom and in order to get back to where that allen set screw lines up I have to move say five down. At this point I can turn the numbered disk but it will have to return to the same spot in order to tighten the set screw again. Maybe I am tired and missing something. I am going to go into the shop and take a look at it. Do you see what I am getting at though. I have instructions on the rear sight, I have to find them and re read it. If I find an answer I will let you know.

ppcshooter1

Figure out how many clicks you need to adjust the elevation drum so the 0 is set for your 200 yd zero. Turn the elevation drum so you can access the allen screw and loosen it so the top and bottom halves of the elevation drum are no longer secured to each other. Hold the top half and turn the bottom half the required number of clicks then tighten the allen screw. Then make sure you have the right number of clicks between bottoming out and the 0 mark.

Marty

Bamban

Warren,

Sorry I missed your call, we were out.

On AR sights, here is one from the USAMU

http://www.odcmp.org/1106/default.as...MU_NOWIND_ZERO

Nez

82nd ABN

Roger that gents I also found some interesting info here.
http://www.earlymaturity.com/AR15.html

art7

You will have to turn off from your 200 zero to get access to the set screw, so you need to do this in relative mode. You will not do this while the rifle is set at the 200 zero.

From your 200 zero, coount how many clicks you have to go to get 0 in your indicated position, Say you need to go 10 clicks clockwise.

Now, go to where the wrench gets to the allen scew. Loosen it, and move the bottom of the drum 10 'clicks' clockwise. I think this will be an estimation, because the actual detents for the clicks are on the top disk, so you will not actually feel clicks as you turn the bottom of the drum. Tighten the set screw,

Now go back to the bottom mechanical zero, come up 7, and the 0 should more or less line up. If you are off by a click or 2, you might have to go back and do it again.

Art

82nd ABN

Understood Art, I need to go back to the range and get a 200 yard zero. I spent most of the day getting the front sight aligned in order to keep the rear sight windage zero. I was loosening he screws too much and tightening the opposite screws making to much of an adjustment and I was chancing the dam bullet left to right until I figured out that I only need to loosen it very little. That is set up perfect and I was finally painting the 10 and x ring having to much fun. I will get back soon and figure out the 200 yard zero and also mark a 100 yard zero.

ppcshooter1

Something has been bugging me since I read this a couple of days ago so I hauled every AR and AR upper out and checked them. Each and every one of them has the check ball for the detent in the bottom of the elevation wheel window. So the detents are on the bottom of the elevation wheel not on the top. One of mine has them on both top and bottom but it is 1/2 minute on one side and 1/4 minute on the other. You remove the rear sight and flip it over to change the adjustment to the one you want.

Marty

dprice3844444

dumb question?if your setting up an ar for match comp,can you use the ar with the removable sight base and have a sight base set up for each distance?

rq375

also check the top of your front sight post, some are tapered and only one of the four sides should face back forcing you to make 360 adjustments only or file.

ppcshooter1

That's actually easy. Each revolution of the front sight is 5 moa. For each 5 mins you adjust the rear sight when setting your zero, you turn the front sight one revolution and move the rear sight back.

Marty

ppcshooter1

I don't see why not. You might have to remember to adjust your front sight for 600 yards or you could buy the Armalite NM carry handle and have the upper receiver's rail drilled to lower the elevation post. I think it is only a 1/4" deep.

Marty

art7

Marty,

Now that you mention it - it makes sense. I said "I think" about the detent being top or bottom because I did not have it in front of me, and was trying to visualize it, but now that I think about it, the hole for the detent ball is the same as the hole for the allen screw. It continues from the carry handle through the opening for the elevation drum, into the upper receiver. So the detent ball and spring are below the elevation drum and the allen goes in from above.