AR Zero Needed

S

Smit

New member
Hello Folks,

I have read a few posts but the more I read, the more complicated this question gets. Looking for a straight-foward answer here:

I want to zero my AR-15 for 100 yards. What is the short distance version that will put the bullet dead zero at 100 yards? Thought it was 25 but I do not think that is correct. Thanks,
 
Everyone has thre own way or method they follow. From the three shot method to "DOPE and HOPE"
My prefered method is at 25 yards with sandbags I zero at 1/2 inch high using the three shot method. 3/8in - 1/2in high at 25yds = 2.5in - 3.0in high @ 100yds.
Aim at bulls eye first shot determines where actual strike is, with out moving the rifle adjust your elevation and windage until the crosshairs (dot) move to the bullet hole. Still aiming at bullseye your second shot should be pretty much there. Fine tune and confirm with the third shot. If it takes 4 or 5 shots don't worry the rifle being zeroed is the important part
Next I move to 50yds for a shot or two for tweaking. Finally I move to 100yds where my zero should be between 2.5in - 3in high.
 
I am thinking if you want to zero that close you will have to zero right at 100 meters.

Given the trajectory of the round when shot from a rifle with sights as high above the bore as an AR-15 I would advise against a 100 meter zero unless it is for a specific function such as a competition.
 
Thanks for the info and website but still looking for a SIMPLE answer to this.
Click to expand...

There is no simple answer, because we have no idea about your rifle, what sights/optics, or what ammo you are shooting.

Sorry, not everything can be spoon fed to those too lazy to type a handfull of numbers and click "calculate".
 
I'm thinking for an exact 100yd zero, you'll need to use a 100yd range.

The general wisdom for ARs is to zero them at 25 or 50 yards, and you'll be within a few inches all the way out to 300 yards, which is more than good enough for most purposes.

If you just really, really want a 100yd zero and absolutely cannot find a 100yd range for it, a 25 yard zero will put you within a half inch or so with XM193 (55gr) ammo.
 
^^^ +1 to the above. There really is no simple answer that you seek. Outside of zeroing it at 100 yards with one type (brand, weight, bullet type, ect....) of ammo there will be other variations. 25 yards will get you close but if you are wanting an EXACT 100 yard zero, zero at 100 yards.
 
Here is your simple answer. If your target is @ 25yds you should be shooting -0.73 inches low for a 100yd zero. This is with a 62gr bullet at 3020 FPS.

Or an even simpler way zero @ 25yds and then adjust your scope down -11 clicks. (assuming your adjustments are 1/4" MOA)

With all that said you will still want to verify and actually shoot @ 100yds....good luck.
 
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Thanks everyone for the input. I knew there was going to be some varied responses due to the nature of the question, but my goal was to be as generic as possible with this.

I havent been able to get to a range and sight the firearm in since it was repaired but last time I attempted at 100 yards with iron sights it was all over the place and hard to judge. Seems as if I will need to invest in a pair of binoculars.

"Sorry, not everything can be spoon fed to those too lazy to type a handfull of numbers and click "calculate". "

Emcon 5 the point of the question was again to get a rough distance for this. At the moment I do not have all the neccessary information to "calculate" an answer. If I did I would not be asking this question.

Thanks everyone,
 
I bore sight my scope first and start shooting 3 shot groups at 100 yards to hit dead on. When I'm solidly in the 10 ring(1 moa or better) I'm zeroed. I use a scope. You wrote that you were using iron sights and I think the military uses a 25(27.34 yards) meter zero. I have never liked or used metric conversions when I shoot.

Your question is valid but there are several considerations like the type of ammo and the type of iron sights you are using.
 
Palmetto-Pride said:
Here is your simple answer. If your target is @ 25yds you should be shooting -0.73 inches low for a 100yd zero. This is with a 62gr bullet at 3020 FPS.
Click to expand...
Only if your sights are 1.5" above the muzzle. On an AR, they probably are not.

Smit said:
Emcon 5 the point of the question was again to get a rough distance for this. At the moment I do not have all the neccessary information to "calculate" an answer. If I did I would not be asking this question.
Click to expand...

Sure you do.

Look up the published muzzle velocity for your chosen ammo. For argument, lets use Winchester white-box, 55gr FMJ @ 3240FPS.

Get a ruler and measure the height of your sights over the centerline of the bore. For A2 sights it is right at 2.5".

Go here: http://www.jbmballistics.com

Choose the Winchester .224 55gr USA FMJ.
Enter 3240 in the "muzzle Velocity" field.
Enter 2.5 in the sight height field.
Enter 100 in the zero range.
Enter 25 in the "Range Increment" field.
Click "Calculate"

That combination with a 100 yard zero will be
25 yards -1.5"
50 yards -0.8
75 yards -0.3

If your rifle and ammo differs at all from that example, you will need to enter it and click calculate again.
 
Perfect, thats what I was looking for. Im not sure which ammo I will be using yet, I usually tend to go for the cheaper stuff. Thanks again,
 
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