A2 Zero @ Service Rifle (and other) Ranges (holdovers etc)

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D.B. Cooper

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Regarding the AR15-A2 rear sight:

For those of you who shoot across the course DCM Service Rifle or NRA high Power, what do you do about zeroing for the 200 yard standing (off-hand) stage?

I understand that the 25 and 300 meter range zeroes are the same because the bullet path cross the sight plane at those two distances. But the A2 sight starts at 300 and goes up to 800 from there. It seems to me that the only way to zero for 200 is to turn the front sight post upward with the rear sight set at 300. (And yes, I realize the sight is graduated in the Metric system while the NRA/CMP ranges are marked in the English system.) But if one does that, the sight will not be correct at 300 for the rapid prone and sitting stages nor at 600 for the slow fire prone stage. Do you just count the clicks on the front post and change it once you're done at 200 (during your first 300 yrd prep time perhaps)?
 
i always used the "national match" sights which are in MOA, not specified ranges. I zeroed at 100, and was 3, 6, and 15 MOA for 200, 300, 600 respectively.

i'm not sure how to work those sights, but i for sure wouldn't want to change the front post between strings.
 
For the post matches that I borrowed A2's from a friends' Arms Room for my team, We set the zero at 300m, and held Kentucky windage for 100m and 200m, then clicked up for 300-600m. It wasn't a whole lot of holdover, ballistic tables will give you the right amount.
 
I guess it works if you're using NM sights. I have a USGI rear sight. Graduated for set distances using M855 ammo. I was hoping for something a little more precise than Kentucky Windage.
 
Things have changed dramatically in CMP/NRA highpower in the last three years.
Optics are the new thing.
4.5x maximum. Weight limit for optics guns.

There is a way to reset the rear sight to go below the 300m minimum. It involves loosening the Allen set screw in the elevation drum and moving it two clicks. I can’t remember the website that details it.
Difference in 300 and 200yds is -2moa.
My AR15 match “handle” is a 1/2 MOA RRA. I have it marked for 200,300, and 600yd settings. FWIW, 600 is one complete turn up, from 300 (20-clicks, or 10moa).
Check out the CMP forum for more details.
 
I guess it works if you're using NM sights. I have a USGI rear sight. Graduated for set distances using M855 ammo. I was hoping for something a little more precise than Kentucky Windage.

Unless my memory is completely off, even the basic A2 rear sight on an AR-15/M-16 has roughly 1-MOA elevation adjustment per click. You don't have to rotate it based on the fixed range settings. You can set it to battle sight zero but you don't need to to use it that way.

Adding Kentucky elevation on top of all of the other inconsistencies in that system (M855 ammo, sling attached to the front sight base and flexing the barrel) is just a recipe for frustration to do better than "hit the bullseye somewhere."
 
With the GI A2 sighted in with the 25/300 meter zero. It should be set at 300 with the small aperture and then the larger (0-2) aperture should be for anything 200 meters and below. Yes the military is only expecting minute of man.

What Goose is talking about is the Revised Improved Battlesight Zero(RIBZ), which is set for 50/200 meter zero. The RIBZ definitely has a flatter trajectory for combat distances.
 
For those of you who shoot across the course DCM Service Rifle or NRA high Power, what do you do about zeroing for the 200 yard standing (off-hand) stage?

If you want to shoot A2 sights in High Power, you will need to get a zero for the shortest range you are going to shoot. If, like me you shoot 100-yard matches, you will want a 100 yard zero as your baseline zero. If the shortest range you are going to shoot is 200, then that’s your base line zero. After that you will need to get a good zero for each yard line and in each position in each yard line. Your 200 zero for standing and sitting is not likely to be the same.
You need to go shoot.

As a side note, this weekend I am shooting a match using my old A2. Gonna go retro.
 
I zero the front sight post at 100 with the rear sight in the lowest position or as close as possible, then count clicks to come up the appropriate amount for 200, 300 and 600 paying no attention to the actual range markings on the rear disc. Just gotta know your MOA per click
 
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