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Old June 24, 2021, 11:59 AM   #1
napg19
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Sight in AR15

I normally sight in my ar15 at 50-200yds. This new rifle I'm thinking of sighting in at 25yds. Question is if I want to take a long range shot, say 100yds. My thought is to just aim 2 inches low at target and I should be close to bullseye. Am I right or wrong. Any help an all opinions appreciated. Thanks
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Old June 24, 2021, 12:33 PM   #2
hub1home
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When I sighted in my AR, I only had a 25 yard range available. I wanted it sighted in for 100 yards so I sighted it at 2 inches high at 25. That gave me a 100 yard dead on.
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Old June 26, 2021, 09:34 PM   #3
HWS
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Why not just zero it at 100 yards? I think the 50-200 zero is the most practical anyway.
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Old June 28, 2021, 04:36 PM   #4
Double K
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Depends on if your using a scope or open sights, and if the sights are on a carry handle.
The higher your sights/scope are above the bore the LOWER your bullet will impact on the 25yd target if sighted in at 100yds. It's not unusual for a scope on an AR to be over 2" above the center of the bore, even a flat top with sights is slightly over 1.5" which would put a bullet over an inch low at 25yds when sighted in at 100yds. Typically a rifle sighted in at 25yds will also hit center of the target around 250yds with the top of the trajectory around 200yds, probably 3" high.
The trajectory of the 223 is relatively flat out to 200yds, the bullet is only shedding approximately 100fps per 100yds.
These are all estimates, informed however because I've hunted coyotes with an ar-15 since 1989 in the western plains.
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Old June 28, 2021, 08:12 PM   #5
jmr40
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The traditional way for military rifles with iron sights was to zero at 25 yards. That would also mean a 300 yard zero. But between 25 and 300 yards the bullet would be above line of sight. Several inches high, and enough to miss if you're shooting at a smaller target. But the original iron sights were designed to work with this method.

On my AR'sn with optics I just zero at 100 and go from there. That works better for me. And now that the military is using optics on all of their rifles I don't know how they are zeroing them.
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Old July 6, 2021, 09:08 AM   #6
baddarryl
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JMR is right. That is called Battle Sight Zero and was designed to be able to engage a man sized target without a sight adjustment to 300. What we do is set it up that way and then figure out drop and rise at 100, 200, 300 and record that and so on....if you have the range of course.
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Old July 6, 2021, 01:08 PM   #7
MarkCO
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Quote:
Originally Posted by jmr40 View Post
The traditional way for military rifles with iron sights was to zero at 25 yards. That would also mean a 300 yard zero. But between 25 and 300 yards the bullet would be above line of sight. Several inches high, and enough to miss if you're shooting at a smaller target. But the original iron sights were designed to work with this method.

On my AR'sn with optics I just zero at 100 and go from there. That works better for me. And now that the military is using optics on all of their rifles I don't know how they are zeroing them.
This.

They have started to call it a 12" zero. The range at which the bullet will never be more than 6" high or 6" low from the aiming point. The new Army rifle qual is a bit harder and they have changed up a few things.

My son is at Basic as we speak. They shoot the qual course at least 5 times, first time with blanks. But they still have BUIS and they still have to zero and shoot with the BUIS once before they move on to the Optic, which they sight the same. He is doing BUIS zeroing today.
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Old July 21, 2021, 01:29 PM   #8
jackstrawIII
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Hornady has a really good (free) ballistics program. Google it.

Just put in some basic specs (velocity, bc, etc) and you can know exactly where your bullet will be at every point along its journey.
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Old July 22, 2021, 04:46 AM   #9
armoredman
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I zeroed my AR at 100 yards, simply because that was what I had been taught to do for decades. I think it will do.
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Old July 24, 2021, 06:30 PM   #10
Nathan
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Try sighting in 0.5” low at 25 yds. That will have you battle zeroed to 350!
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Old July 24, 2021, 08:40 PM   #11
MarkCO
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Try sighting in 0.5” low at 25 yds. That will have you battle zeroed to 350!
Um, nope.
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Old July 25, 2021, 10:58 AM   #12
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I zero my 16” AR at 50. That puts me 1/2” low at 200 (im ok with that).

That zero allows the hold over lines in my Vortex Strike eagle 1-6 to line up ALMOST perfectly at 300, 400, 500 and 600. Again, not exactly, but close enough for field shooting.
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Old July 25, 2021, 01:49 PM   #13
Nathan
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Pretty close….300…minus 0.25” would be better.
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