Well, the answer is .72"

But.... That's dependent on ammo, barrel length and velocity.

There are a few good free ballistic calculators you could get for your phone so you could work that all out on your own.

 

∆ This. The online calculator from gundata.org is my favorite, use the 'advanced" option and measure the center of your barrel to the center of your sight or optic.

 

I am not clear on what you want to do and why you want to do it. What is significant about 36 yards? What is the intended target that requires this zero?

 

Well it is supposed to keep your near zero out to 300 yards. Between 50 yards and 300 yards is only about 5 inches. If you go to you tube there are some instruction videos. One I watched had a ex navy seal who used 70 grain ammo.

 

I use the "Marine" 36yd zero and for 556 and 300BLK and at 25yds you should be approximately a little less than an inch low.

 

I've read a lot about the short range zero, but just wonder if you verify the zero at longer ranges just to be sure??

 

This is what I've calculated for a 10.5" barrel. Very little hold over/under for that zero out to 200 and plenty good enough for defensive work.

 

Here's what a 36 yard zero looks like. LOTS more dope to remember. Not nearly as useful for a pistol length AR. Recall the Marines use a 20" barrel. Your desired zero is not the best one for the weapon.

 

All you need to know about a 36 yard zero. All of my AR's have this zero outside of hunting.

 

OK that is a decent explanation but he did not cover sight height. I know it is an old fashioned set up but there are still AR15's out there with scopes mounted like this.

For the M16A2 with iron sights the instructions 1 & 3 at at the bottom of the zero target achieve the same effect but the 36 yard zero is a bit harder to screw up and trust me soldiers do on occasion get it wrong.

 

I set up a target at about 50 yards - shot a few rounds with my 10.5 AR pistol - adjusted my red dot to hit close to the center and figured I was GTG.

When shooting closer 15 - 25 yards I am a couple inches low - at 100 yards I am a couple inches high.

Did I under think this?

 

I set up a target at about 50 yards - shot a few rounds with my 10.5 AR pistol - adjusted my red dot to hit close to the center and figured I was GTG.

When shooting closer 15 - 25 yards I am a couple inches low - at 100 yards I am a couple inches high.

Did I under think this?

No, you can get a decent idea of what a 10.5" does with XM193 if you look at the data I provided above for a 50 yard zero.

 

The difference in POA and POI will also depend on the height of your sighting-system.

High mounts will put your POI lower at that distance compared to lower mounted sights.

 

...that and height over bore is calculated into the zero so that POI and POA are the same at the first zero point and damn close at the second.

HOB only matters short of the first zero point.

 

Again.... you can look at my provided data to see what's going on.

 

Three dots are fine for me at 25 yards..

 

OP.....don't aim.....just shoot !!!!!

 

"virtually no drop" does not jive with "precisely, mathematically correct".

 

...and not knowing that these zeros correspond to doctrine training and that they have TWO POI at roughly the same POA is just weird.

Like someone is out there zeroing for a single impact at 36 yards with a rifle...

 

Yeah, the guy in the video may not have explained everything, but it seems to me he demonstrated everything (at least between 25 and 300 yds) with whatever ammo it was he tested.

 

The video describes what happens with all of these MPBR zeros. What it doesn't do is explain what is best zero for every shooter and every barrel length.

Mission and tools dictate that. I for one really prefer 50/200 for everything I'm likely to ever encounter and it offers the flattest trajectory with the least amount of hold unders/overs.

 

FWIW the Vigilance Elite target states that it is for an EOTECH with 2.5" rise over bore.

 

50/200 for me for 5.56 ARs

 

What nobody has pointed out is that the 36 or 25 yard zero is using A2 iron sights with the elevation set to it's lowest setting which is only used for setting combat zero. When you rotate the dial up to where you use it for combat your bullets will strike your 25 yard zero target well below your point of aim. For the purpose of zeroing an AR I think we have to assume a standard sight elevation above the bore. If you use an optic which raises your line of sight all bets are off trying to use the numbers from standard iron sights zero and you'll need to call Good Will Hunting and figure it out.

I can say from experience the 25 yard Army zero procedure, not to be confused with a 25 yard zero, for the M-16 A1 (different sight than later models) has the desired impact point on the 25 yard zero target marked with an X well below the aiming point. I do not know at what ranges the trajectory intersected the line of sight but we aimed dead on out to 300 yards on a man sized target with that zero. Back then they said our maximum effective range was 350 yards. We did have a long range aperture we flipped up for over 200 yards if I recall. I don't know if it was just smaller for more precision or was also higher than the close range aperture.

All this talk about rifle sights being parallel to the barrel (they're not) and virtually no bullet drop at 25 yards is not just wrong it's confusing. There's nothing confusing to me about what the OP was asking. The big thing is you have to realize the procedure to achieve your desired trajectory is not the same depending on what site you are using.