Help me figure out my zero problems

[reapur]

Hello,
I have an AR15 with a red dot, both a holosun 503c and eotech xps3.

I've been consulting ballistics calculators from Federal, Hornady and Sterlok pro on my phone.
I'm pretty sure I have a the ballistics for the M855 figured out since it's available all over the internet and strelok pro has it in its database.

73874

So According to these calculators for a 200 yard zero, it should look like the above picture.
The way I see it, I can zero at 25 yards if I when I aim at the bullseye, I let it shoot 1" high, right?
Then at 50 POI should be almost right at POA, just .3 off.

Well I went out today and got the zero at 25 yards, where the POI is 1" high.
Then I went to the 50 yard range, and POI was 6+" high!
I went back to the 25 and it was right on at 1" high, I go back to the 50 and POI is still high.

How is this supposed to work?

Thanks

[00tec]

Anything between 25(ish) yards and 200 (ish) yards will be high. 25 and 200 should be close to the same. Everything after 200 will be low.

[crays]

Try this link: http://www.m4carbine.net/showthread.php?63618-Basic-trajectory-curve-5-56

It's a lot of info in the thread, but read through it several times, and it might help some.

[mattiooo]

This is why chose a 50 yard zero:
http://www.arma-dynamics.com/images/m193---10_5-barrel.jpg?crc=4030418027

This shows the POI from different ranges when POA is the red circle.

This article has a target for setting a 50 yard zero with the target placed at 10 yards. Makes it really easy to dial in. It also has a link to another article with a video that discusses the reasoning.
http://jerkingthetrigger.com/2015/02/13/zeroing-target-50200-yard-zero-at-10-yards/

[mattiooo]

Try this link: http://www.m4carbine.net/showthread.php?63618-Basic-trajectory-curve-5-56

It's a lot of info in the thread, but read through it several times, and it might help some.

That's a great thread.

[crays]

That's a great thread.

And I have those same AD graphics, + more (different barrel lengths and M855 results), and a variety of sight-in targets from another good thread there. The one I posted above was the first one I could find a quick bookmark for.

[Hoser]

I much prefer a 300 yard zero.

300 is where things start to get hard. I want to hold right where I want the bullet to go. At 400 I can aim for the neck and still make a solid COM hit.

Granted most of the targets I shoot are 8-12 inch plates.

Hold bottom of the plate for everything inside 200. Shade the middle for 200-275.

[crays]

I can't even see a 12" plate at 300 yards. LOL


Thank goodness for magnification.

Sent from somewhere

[Irving]

For all the content we have on this site, we don't have many actual shooting related stickies. I hope this becomes one of them. That target diagram is immensely helpful.

[ray1970]

I've always used the 300 yard zero. For me, the 5.56 is strictly for use inside 300 yards anyways. The total "spread" or whatever you want to call it is only eight or nine inches ish so from 25 to 300 yards I can just hold center mass on a torso sized target and squeeze the shot. The spread on the other zeros is somewhere around eighteen inches. That means once you start getting out past 200 yards you better be paying attention or you may miss low.

Just my opinion. Everyone may not agree.

[CS1983]

I'm a 300m zero sort of person myself as well. Not because of any mathematical reason. It's just what I was trained on in the Army and I know my hold points with it. I have no interest in retraining myself unless it's to extend that, though a magnified optic would seem the more sensible solution at that point than just irons.

However, the provided chart is interesting in that it's for a 10.5" launching a 55gr bullet. Since a 10.5" barrel would be more likely used on a CQB style platform, or a pistol, having a low spread from 50-200 seems fairly sensible. I wonder what it would look like from 5m-50m....

[mattiooo]

I'm a 300m zero sort of person myself as well. Not because of any mathematical reason. It's just what I was trained on in the Army and I know my hold points with it. I have no interest in retraining myself unless it's to extend that, though a magnified optic would seem the more sensible solution at that point than just irons.

However, the provided chart is interesting in that it's for a 10.5" launching a 55gr bullet. Since a 10.5" barrel would be more likely used on a CQB style platform, or a pistol, having a low spread from 50-200 seems fairly sensible. I wonder what it would look like from 5m-50m....


I much prefer a 300 yard zero.

300 is where things start to get hard. I want to hold right where I want the bullet to go. At 400 I can aim for the neck and still make a solid COM hit.

Granted most of the targets I shoot are 8-12 inch plates.

Hold bottom of the plate for everything inside 200. Shade the middle for 200-275.


I've always used the 300 yard zero. For me, the 5.56 is strictly for use inside 300 yards anyways. The total "spread" or whatever you want to call it is only eight or nine inches ish so from 25 to 300 yards I can just hold center mass on a torso sized target and squeeze the shot. The spread on the other zeros is somewhere around eighteen inches. That means once you start getting out past 200 yards you better be paying attention or you may miss low.

Just my opinion. Everyone may not agree.

I think the zero you choose is directly related to the purpose for your weapon and what you expect to do with it.

I chose the 50 yard zero specifically because my AR is primarily a home defense weapon (and also a 10.5" barrel) and if I ever have to use it, I don't expect to ever be beyond 25 yards, and probably not more than 10 yards in most possible scenarios. I do have another AR better suited for long range shooting that is zeroed to 100 yards, and would be what I choose for a societal collapse.

With that 50 yard zero, I just put the dot on his chest and I'm good out to 200 yards.

[CS1983]

Do you match your rounds to a home defense purpose, i.e., frangible so you don't have pass-through the dwelling?

[mattiooo]

Do you match your rounds to a home defense purpose, i.e., frangible so you don't have pass-through the dwelling?

I do worry about over penetration but I have yet to find the perfect round. I keep a mag with Speer Gold Dot and a mag with Hornady TAP. I do want to explore a frangible round, I just don’t have a way to test it myself, so I’m relying on the test methods and opinions of others.

[Great-Kazoo]

I can't even see a 12" plate at 300 yards. LOL


Thank goodness for magnification.

Sent from somewhere


It depends how much food is on it.

[crays]

It depends how much food is on it.

You calling me fat? [cigar]

[crays]

73878 73877 73880


ETA: I have 10.5", 14.5" and 18" bbl graphics as well

[Joe_K]

Zero at whatever distance you want your rounds to impact. Confirm what YOUR Rifle shoots with YOUR ammo at any other given distance. I prefer a 50/225 Yard, or a 33/300 Meter zero, depending on what distances I have available to me to zero. If I have my pick the 33/300 Meter is much preferred.


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[reapur]

Thanks fellas, a lot of very good information in this thread.
I've been trying the 50/200 zero mainly because I just plink, but I'm gonna try the 36/300 next time. Every time I get out to the range lately I am confronted with a storm not one hour into the day :)

I may need to check how I'm doing this. If I zero for 50/200, then at 25 yards it will impact about 1.5 low. I figured if I zero this way, just go to the 25 yard range and aim at the bullzeye and have it hit 1.5" low and that would be equivalent to 50 zero.
Is this right or wrong?

[Irving]

It's correct, IF your barrel and bullet specs match what the graph shows.