Fieldcraft Understanding MOA

coues7

coues7

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Minuteman
Feb 3, 2007
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White Mountains AZ
#1
I think I have a semi good understanding of MOA.....minute of angle equals approx. 1" at 100 yards and so on out to 10" @ 1000 yards.

How do I use it on my scope and in exbal? I am shooting a Leupold Mar4 4.5-14x50 M1 LR/T scope and I have exbal.

For example in exbal @ 500 yards with (1/4" MOA clicks) it tells me 11 MOA with -57" of drop. How many clicks or turns do I need?


tHANKS
 
#2
Re: Understanding MOA

You'll get to 600 yds. / 15moa +/- .25moa, YMMV w/ vel., with in the 1st " M1 " elev. turret turn range w/ a 100 yd. zero. on your Leupold scope w/ a .308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: coues7</div><div class="ubbcode-body">For example in exbal @ 500 yards with (1/4" MOA clicks) it tells me 11 MOA with -57" of drop. How many clicks or turns do I need? </div></div>
* 1/4moa = 4 clicks to 1moa
* 11moa being/= (4 clicks of 1/4moa) per 1moa x 11moa dope = 44 clicks

FWIW:
- Once you Set/Determine your 100 yd Zero, Slip/Adj. your Elev. Turret to read "0" then turn right till it reads "11" for your stated 500 yd. Dope.

Your program should show you that or have an option to.
 
#3
Re: Understanding MOA

SPDGG,has it right.

HOWEVER, I would strongly reccomend you remove "clicks" from your vocabulary. With the M1 knob you have 0 - 14 with 15 being back to zero but a revolution up. Each line inbetween the numbers is 1/4 MOA. Zero your knobs so that you are POA/POI at 100 yards. From that point on all you will ever have to do is dial on the number of MOA. In this case turn it to "11" and send it. Which is what SPDGG said
laugh.gif
.
If it's 18.25 MOA, turn it one revolution (15 MOA) and then turn it to 3 and a line (15 + 3 + 1 line = 18.25MOA).

Working in whole numbers is a doggone sight better than trying to count 77 clicks.

Tell exbal that you have 1MOA adjustments and it will give you the answer you seek. This of course assumes your knobs actualy give you MOA corrections. You may also want to get used to knowing that an MOA is 1.047" at 100 yards. The farther you get out the larger the error will be when you start stacking numbers. Knowing what your knobs actualy give you when you click them can change things alot if they are not in MOA.

Cheers, Doc
 
#5
Re: Understanding MOA

Leupold M1 knobs adjust in clicks that are a quarter-<span style="font-weight: bold">inch</span> per hundred yards, rather than a quarter-MOA.

That's a 5 percent error, which, at 1000 yards, will result in about a 20-inch elevation bust.

If you're using Exbal, you want to go edit the Sight Adjustment specs. Change the unit to IPHY, which indicates that, and you'll be closer.
 
#6
Re: Understanding MOA

Boy to I have a lot to learn....now I'm really confused. I have Exbal V6.0 and I know I can change the options.....and I'm with you on not doing "clicks" but rather MOA. 20" error is to much.
i just spoke to a lady at Leupold and she's saying the M1 scopes are 1/4 MOA vs 1/4" @ 100 yards?????
 
#7
Re: Understanding MOA

Gotta check it for yourself, each scope is different and contrary to popular fiction they ain't what they are labled. If you can get to a MEASURED 100 yards, lock down the rifle and dial on 10 MOA. If the scope is in inches the movement will be 10" if it's in MOA it will be 10.47" (10 1/2") that is the rough way to get you into the ball park. Keep doubling things and you can refine it even more.

The error that Lindy refers to is when you start stacking MOA. If it takes you 44 MOA to get to 1K and your scope is only giving you 1"/MOA you are loosing ground with each click/MOA.

1.047" X 44 = 46.068"
46.068" X 10 = 460.68"

1" X 44 = 44"
44" X 10 = 440"

460.68" - 440" = 20.68" ERROR at 1K

A quarter of an RCH in a scope is a whole lot of movement at 100yds. It pays to know what your tools do.

Cheers, Doc
 
#9
Re: Understanding MOA

Lindy and all,

Leupold will tell you anything you want to hear-simple moa or true moa, although their literature says clicks are in inches.

You could get different answers on the same day by the same Leupold tech rep. regarding the same scope in question. My speculation is that they've built some of each concept. Maybe on a good day a shooter could get a feel for what he's got at LR, I don't think I could however.

Regarding testing at 100 yards, I do it with all of my sights used for LR, but field conditions yield mixed results. Just touching the scope can void validity of the result, and most of the time the excercise has not yielded a trustworthy answer. Seems my results are always in between what the conslusion should be.

I'm kinda down on Leupold right now. I got a Mk.4 M2 from them the other day that came with an M3 dial. On other recent occasions, boxes have been marked incorrectly, etc. It's sloppy and does not give me confidence that the left hand knows what the right hand is doing. Still, they build some concepts which fill certain niches better than any other.
 
#10
Re: Understanding MOA

Charles: the method in the link I posted above will tell you exactly what your clicks are. There's no need to guess, or ask a manufacturer. I check every scope I get.

I started doing that when I transitioned from a Leupold 3.5-10X40M3 to a Leupold 6.5-20X50M1, and discovered that I needed 2 more "MOA" to get to 1000 with the latter scope with the same load on the same rifle. Clearly, something had changed - and it was the click value.

And someone observed recently that their U.S.O. PCMOA reticle also turned out to be calibrated in IPHY - inches per hundred yards - rather than MOA.

If you haven't checked a scope, you don't <span style="font-weight: bold"><span style="font-style: italic">know</span></span>. I insist on knowing.



 
#12
Re: Understanding MOA

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: doc76251</div><div class="ubbcode-body">Gotta check it for yourself, each scope is different and contrary to popular fiction they ain't what they are labled. If you can get to a MEASURED 100 yards, lock down the rifle and dial on 10 MOA. If the scope is in inches the movement will be 10" if it's in MOA it will be 10.47" (10 1/2") that is the rough way to get you into the ball park. Keep doubling things and you can refine it even more.

The error that Lindy refers to is when you start stacking MOA. If it takes you 44 MOA to get to 1K and your scope is only giving you 1"/MOA you are loosing ground with each click/MOA.

1.047" X 44 = 46.068"
46.068" X 10 = 460.68"

1" X 44 = 44"
44" X 10 = 440"

460.68" - 440" = 20.68" ERROR at 1K

A quarter of an RCH in a scope is a whole lot of movement at 100yds. It pays to know what your tools do.

Cheers, Doc</div></div>

Doc:

After reading this, talking to J.Boyette, and thinking through it all, this may be the problem I encountered at Mr. Edward's a few weeks ago.

I originally had the NF and switched to Leupold MK4 on the same rifle, with the same load. Needless to say, my dope was all screwed up. I am going to go through Lindy's process and verify all my scopes now.

Jon

 
#18
Re: Understanding MOA

Thanks guys for this great post. When I was at Quantico I had to come up a lot more then I thought at 1,000. And now that I think of it, I was about 20 or so inches off. I was only using data cards and not my own calculations since this was my first 1k. I think I had to go up 44-MOA So I could hit the plates.


I have a NFX on my dept. rifle and can't wait to go out past our 100 yd qual. So far 200yds is the most I got out to on her.
 
#24
Re: Understanding MOA

Here's a tip, don't trust EXBAL! don't trust any ballistic calculator for your data. Just shoot it. shoot 3 different ranges like 300, 500, and 800. take the data and then plug it into the ballistic calculator so that all 3 points match. just change the muzzle velocity until all 3 are on the curve. all the other data for other ranges will be pretty much spot on. i did this for the M107 out to 2000 meters and it was never more than 1 MOA off.
 
#26
Re: Understanding MOA

Dope derived from actual shooting is always preferable. A person who always shoots under similar conditions has no need for a ballistic program.

Once the ballistic program is "tuned", though, the ballistic program is a valuable tool when the conditions are substantially different from normal - like shooting at a higher altitude, in a radically different climate, or shooting at significant angles. It's also useful for tasks like quickly calculating holdovers/holdunders from a non-standard zero.

It will help one get <span style="text-decoration: underline">closer</span> to making a first-round hit.

Nothing except the grace of God will guarantee one a first-round hit.

 
#28
Re: Understanding MOA

Ok so I am trying to get started on fine tuning my "dope cards" for each rifle and this is what I have learned so far (I think).

1) Use Lindy's method to see if I have inches or moa adjustment in my scopes (this may explain some things I have been having trouble with at longer ranges).

2) For my Leupold 3.5-10 M1 scopes do up the cards in either 1" per 100 adjustment or 1 MOA per 100 adjustment not clicks (I have always logged clicks)...so 11 moa plus 2 clicks gets you to 46 clicks...makes sense.

3) Same as #2 for my M3 only click values change. Develop card in either 1" per 100 or 1 moa per 100.

4) For my Unertl Sniper check but I believe it is 1 moa per 100 with the lever for the subdivisions

5) For my S&B USMC scope which is in cm how would I set it up....in cm clicks (back to the old click method)? How many cm in one mil (10?) and set the card up for mils instead of moa? I have only shot the S&B at 100 yards to zero it so have not even started the card for that.

I figured once I get the units figured out I would use the JBM calculator to run a spread sheet...transpose it onto an Excel spread sheet and leave room to pencil in the actuals and make changes based upon field experience. Does this approach look sound?

To date I just have been going out to a known distance range and taking notes to figure out the dope by trial and error. While fun to do with the higher cost of ammo I would think that using technology to at least keep me on paper would be a much better approach.

Help with the whole concept and the cm adjustment and the units that should be used would be appreciated.

Thanks
Pat
 
#29
Re: Understanding MOA

Dope derived from actual shooting is always preferable.

Yeah, there is an echo in here...
laugh.gif


I have Leupold scopes with M1 turrets which adjust in inches per hundred yards, rather than MOA.

But I keep dope for my loads in MOA, and then make a note about what turret setting I need to achieve that elevation. That way, if I go to a scope which does adjust in actual MOA, I don't have to re-figure.

On one particular scope, for example, the 100 yard zero is at 4 hash marks. I put the number of turns in square brackets for notation.

36 MOA on that scope takes [6]8-1, which means an indicated up two turns, i.e., [6] for the number of hash marks, plus 8 MOA minus 1 click.

That means that I actually have to dial 37.75 indicated MOA to get 36 <span style="font-style: italic">actual</span> MOA.

Your S&B scope does not adjust in cm.

It adjusts in 0.1 milliradian, or a tenth of a mil for short, and that's how you should keep you data for that. For that same elevation noted above, it would be 10.5 mils.
 
#30
Re: Understanding MOA

To add to what lindy said, with your Unertl Sniper, I'm assuming that is a MST 100...

You don't record the dope in MOA, you use the BDC turret and with the fine tuning adjustment. The information should read, 5 +1 for 500 yards, or at say, 400 yards, 4 -2... you dial the number to equal the range then put in the amount of fine tuning +/- as necessary.

The rest Lindy has covered.
 
#31
Re: Understanding MOA

If you want a good resource for study, the range simulator here contains very good classes on using your scope and getting good reads. It also gives you some good 1000 yard study without wasting ammo. When you are hitting 1000 yard targets at varying temps and altitudes then you know you have it licked.
 
#32
Re: Understanding MOA

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">
On one particular scope, for example, the 100 yard zero is at 4 hash marks. I put the number of turns in square brackets for notation.

36 MOA on that scope takes [6]8-1, which means an indicated up two turns, i.e., [6] for the number of hash marks, plus 8 MOA minus 1 click.
</div></div>

I think I have it (maybe) so your particular scope rifle combo zero is up four revolutions set at zero. To dial in elevation you show [6]8-1 which is the original 4 revolutions for zero elevation plus 2 full revolutions (to zero) plus 8 (32 clicks on a 1/4" per click scope so set at "8") minus 1 click.

So a scope with zero stop would be [2]8-1 as your first 4 revolutions would be taken up by the zero stop. That will take a bit to get wrapped around but it would work with mils or moa as long as I used the correct card/unit of measure with the correct scope.

So in a S&B metric would you log it [1]8-4 or [1]7+6 for one full revolution (I believe that is 11 mils) plus 8.6mils or a total of 19.6 mils.

I am thinking that I have got it but then again????
Thanks
Pat
 
#33
Re: Understanding MOA

You have it right.

The S&Bs tend to be either single-turn, though, or have two turns with a cap on top which turns yellow when you're on the second turn, and the numbers for the second turn are in yellow, so it's hard to get lost.

It's only multi-turn scopes with no zero stop which you need to keep track of the hash marks.
 
#36
Re: Understanding MOA

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tigerbikes</div><div class="ubbcode-body">With the potential confusion between 1 click = 1 MOA and 1 click = 1", is there any compelling reason to go with an MOA scope? Why not use Milrad? </div></div>

If you verify your gear, there is no particular advantage in choosing one over the other....with a few exceptions like using a Mil-dot Master since it is set up for Mil's and MOA but not for IPHY.

Some users, like myself, lean towards thinking in inches and MOA seems attractive. I didn't think IPHY would be as useful as it is becoming to me. The math get's pretty easy when a 12" high target appears as 6 IPHY at 200 yards.

They are all forms of angular measurement. All will work.
Ease of interface to other shooters/spotters-calls/equipment may be a good reason to choose one over the other, but they all work.

Most important is to verify the equipment.
A mil-based scope manufacturer can put out gear with errors in adjustments or subtension too. Being Mil-based does not preclude lack of compliance to a standard.

This is just my opinion, and I am open to more info that may or may not change my opinion.
laugh.gif
 
#37
Re: Understanding MOA

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">If you verify your gear, there is no particular advantage in choosing one over the other....with a few exceptions like using a Mil-dot Master since it is set up for Mil's and MOA but not for IPHY.</div></div>

No, it's not.

Here, however, is an easy method to set up a Mildot Master to work with a reticle calibrated in IPHY:

Bearing in mind that with a reticle calibrated in IPHY,

<div class="ubbcode-block"><div class="ubbcode-header">Code:</div><div class="ubbcode-body ubbcode-pre" ><pre>
target size(inches)*100
range(yds) = -----------------------
image size(IPHY)

</pre></div></div>

you need to make a new "Target Range" mark on the Mildot Master.

Choose an easy one to figure. On the MOA scale on the right side of the Mildot Master, set 5.0 MOA - actually, for this purpose, IPHY - opposite 30 inches on the Bullet Drop slide.

That corresponds to a range of 600 yards. Carefully take a fine-point Sharpie, and make a mark just above the regular "Target Range" arrow opposite 600.

Now cover that mark with clear tape to keep it from wearing out, and your Mildot Master is now set to work with reticles calibrated in IPHY.

Just set the inches of the target size on the Bullet Drop slide opposite the number of inches the target measure on the reticle on the MOA scale, and read the target range on the mark you just made.

I didn't originate this method - it was shown to me by someone else, whose identity I cannot remember.

If you have a reticle like that, though, which include the U.S.O. PCMOA reticle, and the new one Randy just came up with which U.S.O. will build, it's a neat trick. It also works with the IPHY ranging reticle which is on the left side of the Horus H25 reticle.

 
#39
Re: Understanding MOA

It was probably Doc that I learned the from - but I'm old, and I forget stuff.

It's a neat trick, though, with the proliferation of IPHY reticles, because using the MDM is still the fastest way to do those calculations - and the most accurate, because you can very easily check image sizes just above and below what you think the reticle says, to see how much change it makes to the range.

To hit targets beyond about 700 yards, you're going to have to measure them to the nearest 0.05 mils - and that ain't easy.
 
#40
Re: Understanding MOA

I am on your heels in the "old" department.
laugh.gif


I like using a Mildot Master too. It seems to come out first during every UKD session.

How fine do you feel you can resolve a targets size in mil's?
Just curious what your experience is.
 
#41
Re: Understanding MOA

I think I can do 0.05 mils with reasonable repeatability, in conditions where mirage is not too bothersome.

It takes practice - and cheating, which is the same thing.

To enhance your ability to measure 0.05 mil, set up a target a pre-determined distance away which will result in that as a measurement. For example, a 12 inch target which is 606 yards away should measure 0.55 mils. A 12-inch target at 513 yards will measure 0.65 mils, and so forth.

Set one up, and see what it looks like in the reticle. You can see that it's bigger than 0.5, and observe that it's smaller than what would be 0.6.

Also, measure targets which are both light and dark colored. Light colored targets in bright sun look bigger than they are, and dark ones look smaller. Mil the inside edge on the light ones, and the outside edge on the dark ones.

Do that enough, and you'll get better at detecting a difference that is less than 0.1 mil.

Not many people will bother, but, then, not many people are anal retentive enough to reproduce a barricade they had to shoot off at a match, in order to practice doing that, even though they no longer shot matches at that facility. I can see one from where I sit...
laugh.gif

 
#42
Re: Understanding MOA

Thanks, Lindy.
I now have some drills to do next range session.
I have not attempted such fine resolution of targets so far.
I still consider myself a novice at range estimation with a reticle.

You are a very "prepared" guy. Hope to meet up with you someday.
You are skipping "SHOT", right?
 
#43
Re: Understanding MOA

Thanks! However, I don't have to actually work for a living, so I have a lot of time to think about this stuff - and how to teach it to others, particularly to people who need to be good at stuff but don't have a 1000 yard range outside the front door to go practice on.
laugh.gif


 
#45
Re: Understanding MOA

Well I must have done it wrong. I took a 2x12 measured down 36" and stapled a 9x12 white envelope witht eh upper edge right at 36". I then set-up on the porch and using my Swarovski and a Benchmaster to hold the rifle, set-up at 100 yards. I put the range finder on a tripod to make sure the reading was repeatable right at 100 yards. The then lined my crosshair (using a Leupold M1 LR) on the top of the board and dialed up 36...I was into the paper 1". I did it several times then dialed in to the top edge of the paper ...35 clicks (140 1/4" clicks). I then used another rifle with a Leupold M1 LR...35 clicks. I am assuming the scope is 1/4" at 100 and not 1/4 moa and that I was either not at 100 yards or was doing something incorrectly??? I was aiming down about 8 to 10 degrees but figured the range finder would read actual range to target. The board was pretty darned close to verticle as I wired it to a fence post. I think I found out what I needed to know but wish there was a barber pole available to do the same thing at an known distance with a know height.

Lindy thanks for link...it was a good one.

Pat
 
#46
Re: Understanding MOA

Pat: think about the precision required in the adjustment mechanism to get 140 clicks to come out exactly right. Pretty difficult.

If I read what you're saying correctly is that both scopes take an indicated 35 MOA to get to 36 inches at 100 yards.

35 times 1.047 inches per MOA would be 36.65 inches. So, it may be that those particular scopes are just a bit shy of an actual MOA measurement. Your actual adjustments work out to 1.029 inches per "MOA" instead of 1.047

That's not a problem - I suspect most scopes are going to be a bit off. But now you know what dialed 35 will get you - and that's precisely the point of the exercise - so your time was well spent.

The error you measured, though, works out to 1.72 percent. If your distance measurement using your laser rangefinder was off one yard - and remember that most only report to the nearest yard - that would account for some of the error.

That's why I recommend using a good tape measure for the distance measurement rather than a laser - with a tape measure, carefully used, you might be off a couple of inches, but certainly nothing approaching an entire yard.

Cheers!

 
#47
Re: Understanding MOA

Lindy,

I really should get to a known distance range and inquire if the yardages have been measured exact. I would suspect that the excersize measured at 300 yards would be much more accurate than at 100 yards assuming the yardage is accurate. The other thing is holding the rifle perfectly still. While the crosshair came back to the top of the board when dialed up something more secure would help eliminate error as well. Once again, as you have said, nothing beats actual field testing to see what the actual requirements are. I am going to continue to look for a "good" range that I can try this again only at a longer distance.

Pat
 
#48
Re: Understanding MOA

Pat: My experience has been that 100 yards, carefully measured, is about the best you can do. Most people aren't going to carefully measure distances at ranges, and even a 2 yard difference in where you are at 200 yards is a 1 percent error.

If you shoot pretty much under the same conditions, so you have actual dope on your rifle and scope at distance, then the finicky-ness of doing this kind of test is unnecessary.

However, as I noted in my experience with the M1 Leupolds, that 5 percent difference between IPHY and true MOA, at 1000 yards, amounts to a 20 inch vertical bust with a .308.

If you shoot under many different conditions, where you will be relying on ballistic software to attempt first-round hits at extended distances, they you're a lot better off if you know precisely what your scope does.
 
#49
Re: Understanding MOA

OK, hopefully this isn't a stupid question. On a Bushnell 3200 10X40 Mildot optic, I have it zeroed at 100Y. Based on my ballistics calculations, should I make the corrections (range and windage) by holding at the marked increments in the reticle or turning the dials. Next question, are the marks on the knobs in mils or MOA. The marks on the knobs are 1|||2|||3.....

Right now I have a 100 yard zero and have marked in my log book where to hold for 200y (wind conditions have been irrelevant thus far). Need to figure this out before I go turning knobs and wasting $$$.
 
#50
Re: Understanding MOA

The click values are 0.25 MOA. Once you have established your 100 yard zero then you would set your knobs to read zero on the dial and then make note on which revolution the knob is on at your zero. If you have ballistic calculator data on the MOA values of your elevation needs out to the distances you are going to shoot, then in a perfect world you can simply dial in the number shown necessary to be on target. 4 clicks on the scope is a MOA and a MOA is a MOA regardless of distance. Your knob is marked with the numbers for the full MOA values and then the lines in between are .25 MOA. So if your data says that you need to put in 4.5 MOA then you would turn the knob to read 4 and then add two clicks and use the crosshair as normal.
 
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