Help with AR-15 Zero...

[David4516]

Wondering what distance you guys like to zero your AR-15s for?

My wife and I hit the range today to zero her new-ish rifle. She's new to rifles in general (she likes pistols). I am not new to rifles, however I am new to ARs (been more of a bolt or lever gun guy until recently). I know that the military zeros at 25 meters (they like metric, not yards) and that is supposed to be about dead on again at 300 meters, with the point of impact being a little higher than the point of aim between 25M and 300M.

I used a free online ballistics calculator (see attached photo) using the data for my reloads and the 16 inch barrel. We're shooting 55gr (Hornady flat base soft point) at about 2,800 FPS (25.0gr of H335 powder). This told me that we should be almost dead on at 200 yards if we zeroed at 25 yards. This wasn't the case...

The range we shot at had positions for 25, 50, 100, and 175 yards. We zeroed at 25, with both sites. I guess I should mention what sights we're using. She's got a fixed front sight and a flip up MagPul rear sight. She also has a 3-9X scope on a quick detach mount. Here is the mount:

http://www.amazon.com/Weaver-Thumbnut-SPR-1-Inch-Mount/dp/B00AU6DDTY

So we started with no scope, zeroed the irons at 25 (she was shooting one ragged hole at 25 yards), then attached the scope and zeroed it at 25 yards as well. When we started shooting at the more distant targets, the point of impact was very high. We decided to leave the irons set for 25 and just mess around with the scope. We re-zeroed it for 50 yards, then shot it again at 100, and it was still hitting very high (like the very top edge of the paper, probably 4 or 5 inches high if not more). I have always been told that .223 is a flat shooter but it seems more like a rainbow to me.

Am I just doing something wrong? Did I put the wrong data into the calculator? Are these calculators even that accurate? Should we just zero it at 175 yards and aim a little low if we shoot a closer target? I'd like to zero it for whatever distance is going to let her shoot it over the widest area without having to adjust for bullet drop one way or another. Like hopefully plus or minus maybe 2 inches?

I will need to re-zero my own AR after this I think too. It's got a red-dot and back up irons both of which I have set for 25 yards (same ammo and barrel length on this rifle). I haven't' shot it much at distance yet...

 

[David4516]

Ok I may have just answered my own question, plugged some different numbers into the calculator (see attachment) and this looks like the 175 yard zero might be good. Wondering if we go for this, should we also set the irons for a 175 zero? Or just leave them set for 25?

Still very interested to know what everybody else does, and does your choice in sights/optics impact your decision? If you have BUIS do you zero them at a different distance than you do your scope or red-dot? Any help/info/advice you guys could share would really be appreciated. Thanks again.

 

[rskent]

I try to keep it simple, hundred yard zero.

 

[SVTOhio]

100 yard zero with my scope and 25 yard zero with my BUIS. Scope is for hunting and BUIS are in case SHTF.

 

[GRIZ22]

You can zero your AR at whatever range you like. When the military sight in at 25 meters, the strike of the round is below the point of aim. This is because the sights on a M16 are high above the center of the bore compared to most rifles. Does your ballistics calculator take into account height of sights? The high sights are what create your rainbow trajectory.

I sight both my irons and scope at 200 yds. Bullet is about an inch high at 50, 2" high at 100, zero at 200, and about 5" low at 250. A center mass point of aim will put the bullet in the torso out to 300 yds.
This meets my needs.

BTW, the Army uses meters to be consistent with other NATO countries not because they like them. The Navy and Marines still talk in yards because that works better in a maritime environment.

 

[1911 guy]

Personally, I like a 50 yard zero.

For close range use mechanical offset, from 50 yards to 250 yards the bullet path is never more than 1.75" from line of sight and for most civilian use that's plenty.

 

[briansmithwins]

I do a rough zero at 50 yards and then fine tune it at 200. That should put the bullet strike within +- 2.5" of the line of sight from the muzzle out to around 250 yards.

BSW

 

[tuj]

I personally use a 100 yard zero on my 20", and a 25 yard zero on my 16"

 

[VA27]

Personally, I like a 50 yard zero.

For close range use mechanical offset, from 50 yards to 250 yards the bullet path is never more than 1.75" from line of sight and for most civilian use that's plenty.

With the typical AR this is the best plan for iron sights/dot scopes.

For a hunting type scope my personal preference is to sight in at 100 and memorize holdovers. YMMV.

 

[strambo]

The 2 best AR zero ranges are either 50yds (also near dead on at 200) or 100 yds. Anything else will be too much of a rainbow trajectory on a 16" gun. The 25/300 meter zero works well with a 20" barrel, but not a 16".

 

[1911 guy]

Even with the 20" barrel, a 25 meter zero is "minute of man" and designed for 300 meter zero. It's several inches high even at 100 yards or meters and not terribly suitable for most use. Whacking a torso out to 300, yes. Hitting anything smaller, not really.

 

[rcmodel]

It isn't actually 'zeroed' at 25 yards.
It's only minute of man zeroed.

If you want to hit small stuff at long range, zero it at 100 yards so it is shooting 1 1/2" to 2" high.
Or zeroed exactly dead centered at 200.

It will be on as far as you can see a small target.

rc

 

[Inebriated]

Check out this link for a better understanding of trajectories.

 

[4thPointOfContact]

It's not popular as most ranges are not marked for it, but I'm a fan of the 37 yard zero.
The bullet will be 3" or less all the way out to 100 yards, never rises more than 4, and doesn't drop down below line-of-sight until far past what I consider serious social encounter engagement range.


I did have to do a little extra figgerin' on the pre-marked MTAC scope though.

 

[jimbeaux82]

I use 100 yard zeros for my AR's, both for BUIS, Red Dots as well as one equipped with a scope. I find that sighting in 1 - 1.5" low at 25 yards will put you very close to a 100 yard zero. Using a 100 yard zero, just be aware of sight offset if shooting a small target at close range.

 

[C-grunt]

Great video done by Travis Haley on AR zero's. Very much worth the 8 minutes.

https://www.youtube.com/watch?v=g9oXGT55cV8

I prefer the 50 yard zero for my red dots and 100 for my scopes.

 

[ColonelKorn]

I zero for 200 yds. with the scope, and 50 with iron sights.

 

[Driftertank]

I found that a 50yd zero on my 16" carbine with PMC X-tac 55 is so close to a dead on 200yd zero as to make the distance within my CEP. That is to say, 50yds is the same as 200yds.

Regarding the disparity between your ballistic chart and real life findings; what did you set as your height-above-bore?

ETA: I read it. I think 1.5 is too low. I don't remember the actual number for an AR, but IIRC, 100% co-witness rings are 1.4 above the rail (?) which is about 3/4" or so above the bore. Correct me if I'm wrong

 

[David4516]

GRIZ22, Driftertank, I think you guys are right about the sight height thing. I believe I set it too low on the calculator and this is why the numbers weren't matching my real-world experience at the range. I changed the sight height variable on the calculator and for a 25 yard zero it said I'd be about 7 inches high at 100 which sounds pretty close to what I was actually getting.

We will try the 50 yard zero next time, probably for both the scope and the irons. If a 50 yard zero puts you pretty much dead on at 200, then it should be perfect for us (don't plan on shooting past that distance anyway)

 

[Malamute]

The link from Inebriated to the M-4 Carbine forum is excellent. It seems complicated, but read through it, it really isnt that difficult once its understood. Not just the first post, but the first few.

 

[1911 guy]

I think the AR is 2.4 or 2.6 inches.

 

[readyeddy]

I would choose between a 100 yard zero or a 230 yard zero (2.3" high at 100 yards) using M193 (3000 fps/16" barrel).

With a 100 yard zero, you will be 2.6" low at the muzzle, 1.5" low at 25 yards and 3" low at 200 yards.

With a 230 yard zero you're close to MPBR, where you're never higher or lower than 3" out to 260 yards. I usually use MPBR for hunting.

 

[Comrade Mike]

My RDS is zeroed at 50 and my irons are at 25. I have no problems from 0-250 with my RDS and have to hold about a dot diameter high at 300

 

[strambo]

Depending in your dot size that sounds right. I qualify 50-300m with an M4 and M68 CCO. I zero for a 50/200 zero which has me impacting 2.5cm low I believe on our 25m zero range. From 50-200m I aim COM. At 250 I aim a hair high (about center chest) and at 300 I put the dot on the neck.

 

[ScottsBad]

I use a 100 yard Zero. But first you need to decide what your primary ammunition will be. There is a difference between most .223 loads and the usually hotter 5.56 military loads. And of course the weight of the bullet is a big factor. So determining what ammo you want to zero for and what you plan to use your rifle for are major considerations.

I have my ARs set up for Federal M855. They shoot differently with PMC Bronze, PMC X-Tac M193 and M855, CBC 62gr 5.56, CBC Mk262, Wolf Gold, etc. Each ammo is different.

I saw no reason to zero for better quality ammo like the CBC Mk262 clone because that is not what I shoot when practicing. If you shoot competitively you will want to zero for your competition round. Otherwise just zero for what you keep in bulk or use professionally.

Pick a point about 1.5 inches below the bull and mark it. Place the target at 25 yards and aim at the bull. Adjust until the point of impact is the mark 1.5" below the bull. Then confirm zero at 100. Most of the standard crap ammo will only give you 2 moa of consistency at 100 yards. You might have to adjust to get a reasonable 100 yard zero.

I plan to use my ARs for home defense and fun shooting so I picked 100 yard zero. A 100 yard zero gives me a pretty flat trajectory for 25 to 150 yards for defensive and fun shooting which is mainly where I plan to shoot. If I want to accurately shoot farther I have .308s for that.

I used to use a 50 yard zero but found that the 100 yard zero gives me a better trajectory at the distances I'm most likely to be shooting.

So it really depends on what type of shooting you plan to do and what type of ammo you plan to use.

Oh, and another consideration is the type of optic you use. I use Aimpoints and a couple 1-4X scopes. I think most folks go with the 50 yard zero, but that puts the shot a little high at 100 which is a much more likely distance I'll be shooting than the other zero for the 50 yard zero which is 300 yards. If you see what I'm getting at.

Anyway, M4Carbine some info and free targets for 100 yard zero.