Mildot Reticle and MOA Turrets

[rckendall]

I am a target shooter and have always understood the sights/scope in MOA. I have taken an interest lately in the military sniper rifles and have been trying to educate myself on them. A couple days ago I saw a YouTube video of a M40A1 rifle that had been built as close to the originals as possible. He went into some detail about the scope that was used, a Unertal 10X. He stated that he had a love/hate relationship with it because it was so difficult to use, compared to the ones we now have. These were issued in the mid sixties with the original M40s.

Besides difficulty getting the turrets adjusted for zero with the rifle, it used a mildot reticle and moa turrets. He didn't elaborate much on the reasoning behind it, but did explain how they were set up for the military. The vertical scale was in Yards, 5 being for 500 yards, etc. The windage was in 1/4 moa.

He mentioned that the reticle (mildot) allowed the user to estimate distances and then easily transferred to the turret. I know that technology has advanced greatly over the years but I wonder how the mildot reticle would be used to estimate distances and is it easier than a similar reticle in MOA?

Any insight would be appreciated. Thanks,
Richard

 

[Zero333]

Mildots are metric and moa is imperial.

The conversion math is a headache. Best is to have the reticle and turrets in the same measurement.

One is not better than the other. Just different scales.

 

[dsculley]

Really not that difficult to use. You are going to have a dope card for your vertical/wind adjustment in the format as your turrets. Unit of measure can be either meters or yards. (500 m = x moa or 500 yd = y moa) It is easier to use meters for ranging with the mildot reticle but there are equations for using imperial units as well. So, with all that said you set up your ballistic table using meters & MOA, use meters for ranging with your reticle or range finder.

If you want some inexpensive practice go to shooterready.com and get their long range shooting app. This app will give you a chance to see just how difficult it can be to range accurately/effectively with a ranging reticle. When you are practicing ranging in the app, remember that you are given the various dimensions of the target. In the real world, you may not know the target size, or it may be leaning and appear smaller that it is, or heat waves (mirage) may make it difficult to accurately bracket the target in the reticle, etc.

 

[Depart123]

I am a target shooter and have always understood the sights/scope in MOA. I have taken an interest lately in the military sniper rifles and have been trying to educate myself on them. A couple days ago I saw a YouTube video of a M40A1 rifle that had been built as close to the originals as possible. He went into some detail about the scope that was used, a Unertal 10X. He stated that he had a love/hate relationship with it because it was so difficult to use, compared to the ones we now have. These were issued in the mid sixties with the original M40s.

Besides difficulty getting the turrets adjusted for zero with the rifle, it used a mildot reticle and moa turrets. He didn't elaborate much on the reasoning behind it, but did explain how they were set up for the military. The vertical scale was in Yards, 5 being for 500 yards, etc. The windage was in 1/4 moa.

He mentioned that the reticle (mildot) allowed the user to estimate distances and then easily transferred to the turret. I know that technology has advanced greatly over the years but I wonder how the mildot reticle would be used to estimate distances and is it easier than a similar reticle in MOA?

Any insight would be appreciated. Thanks,
Richard

The first Unertl mil-dot scopes were issued to the marines in 1978. They, along with the US Army's Leupold M3A in the early 80's had moa turrets for wind and elevation, and mil-dot reticles for ranging.

The two most popularly taught formulas being:
target size in inches x 27.78 / the objects apparent size in mils = distance in yards
target size in yards x 1000 / apparent size in mils = distance in yards

in meters:
size in inches x 25.4 / mils = distance in meters
size in meters x 1000 / mils = distance in meters

In the late 70's there was a push to go metric for everything. The Europeans had been using mil reticles for a while and in the interest of standardization, we started using them also. However, because of the seemingly close relation of moa to inches and the lowest common denominator which would have to use these scopes, the services deemed it a bridge too far to teach adjustments in mils.

This is of no consequence in elevation. Once a target is ranged, it is no difference to dial 10 mils or 34 moa. But when you go to adjust for wind, you most often hold off for wind. All the formulas then in use were moa formulas, the windage adjustments were in moa....but the reticle was in mils...thus the conversion headache.

If a shooter is comfortable in both systems it is no trick to use moa for elevation and the appropriate mil wind formula for hold offs. There would still a conversion if the shooter needed to dial for a prevailing wind when shooting movers, for instance.

 

[rckendall]

Thanks for the replies. I guess I need to practice some with it until I get a feel for it, and I will look for that app. Thanks.

Now the military is using the metric system, aren’t they? They use kilometers and meters etc, I think, and maybe once they get used to that system other aspects of it makes sense. It seems complicated to use them both for a single senereo. I like that they had the elevation turret simplified with numbers that matched the yardage, with a secondary adjustment for fine tuning it for each rifle.

Thanks again,
Richard

 

[Depart123]

Thanks for the replies. I guess I need to practice some with it until I get a feel for it, and I will look for that app. Thanks.

Now the military is using the metric system, aren’t they? They use kilometers and meters etc, I think, and maybe once they get used to that system other aspects of it makes sense. It seems complicated to use them both for a single senereo. I like that they had the elevation turret simplified with numbers that matched the yardage, with a secondary adjustment for fine tuning it for each rifle.

Thanks again,
Richard

The military uses meters now.

Even though the radian, and therefore the milliradian is an SI unit, it matters not. It is just as easy to use moa with meters as it is to use mils with yards and vice versa. The reason is because you can divide literally ANY unit of measurement into quarters or tenths.

0.1 mils is 1/100th of a meter at 100 meters and 1/100th of a yard at 100 yards. It would be 1/100th of a cubit at 100 cubits. All the same can be said for moa. It was the mixing of the two that brought all the fuckery.

 

[Mr.Knowit all]

I would never run the two together. I try to keep everything simple...easy... as little confusion as possible.
I know Leupold scopes were like that for years a Zeiss scope I had was Mil-dot and MOA turrets.

 

[Vamike9]

When time is of the essence and the pressure is on the last thing you want to be doing is complicated math.
Like many of the replys have said I'd match the turrets with the reticle.

 

[rckendall]

I agree that it seems complicated. I just wondered if there was something I was missing. They had the elevation knob numbered so the yardage was easy to set, but the estimating distance part is something I have never needed to do.

 

[Calgary Bill]

I prefer the MOA system. I tried mil dot but just didn't like it. To each his own.
Bill

 

[_Raining]

IIRC the Unertal 10x has yardage on the turrets and another knob to adjust fine tune with a +-3 MOA range. You need the fine tune because of ammo differences and environmentals (Hot air is less dense and thus there is less drag on the bullet).

Since it is a fixed power scope, you don't have to worry about FFP vs SFP.

But, if the reticle does not match the turret then you have to do some conversions if you measure a miss with the reticle and then want to dial that value into the turrets. If you are just using holdover for a fast follow up shot then it doesn't matter in the immediate future but you will need to make conversions if you want to take notes and use that data point to influence your future adjustments on the scope (If you ever heard someone say DOPE, it means data on previous engagement). AKA, the reticle shows you are X mils high, then you just aim X mils low using the reticle and you will get a hit. BUT you then write that down along with the days conditions and now you need to convert that mil value to MOA so you can use it for the fine tune corrections in the future. That is a conversion you wouldn't need to do if the fine tune was in +- MIL instead of MOA.

Now what most people do today is not have a yardage on the turret (BDC or Bullet Drop Compensater) but instead just have it in MOA or MIL adjustments. Then you have a way of figuring out your environmentals usually via a kestral meter or something similar and you plug in DA (Density Altitude) and ambient air temperature into a ballistic calculator and it will tell you what MOA or MIL you should dial for 500 yards. DA is a combo of pressure, humidity and temperature which affects drag and the ambient air temp is used to adjust muzzle velocity because powder burns faster when it is hot. Some devices like the kestrel with AB (applied ballistics) has the ballistic calc built into it. So you just pull it out, turn it on and select your rifle profile and it will tell you want to dial for a given distance.

A FFP (first focal plane) scope will have the reticle gets zoomed in or out when you change the magnification on the scope. So no matter what magnification you are at, the reticle will show the same value for measuring an object. A SFP (second focal plane) scope will not do this, and thus the reticle is only "accurate" at one magnification value. I use quotes around "accurate" because it is technically always accurate, you just need to use the magnification value in the calculation. Aka if the document that comes with the scope shows each hash mark in the reticle is .2 mil at 10x magnification, then at 20x that hash will be .1 mil...I think (it could be .4 but I believe when you double the magnification, you halve the hash mark value).

Assuming the reticle is in the same unit as the turrets, then:
With a FFP scope, it doesn't matter what magnification you are on. If you measure a miss low, high, left, or right, you can just dial that measured value into the scope turrets and be on target.
With a SFP scope, you will need to calculate the appropriate hash value before you can dial it into the scope unless you are at the magic magnification number where the reticle is "accurate".
If the reticle does not match the turrets then you will need to do an additional conversion before being able to dial the correction into the turrets, even with FFP.

The same applies for ranging a target with the reticle, SFP has a conversion if you are not at the magnification listed where the reticle is "accurate" while a FFP will not have that stipulation. But unless you are playing a game or killing people then you wont have to do this. Animals you are hunting don't typically have the technology to detect your laser rangefiner and spot your position. By playing a game, I mean a PRS stage where they tell you that you must use your reticle to range the target, most of the time they will tell you how far away the target is. In F Class and BR, you always know how far away the target is.

 

[XTR]

The standard until not that long ago was mil/moa. About 9 yrs ago I seem to recall some scopes from a military performance test showing up on the for sale pages over on Snipers Hide. I think they were from USO. In any case, the ones made for the USN tests (read SEAL) tests were still spec'd mil/MOA. The reticles got put in the scopes for estimating distance before they started teaching mils for elevation and windage changes.

MOA and MIL are just different ways to measure an arc of a circle. As it turns out in MOA the basis was to divide the circle into 360 degrees, then break each degree into 60 Minutes Of Angle (MOA).

In radians the length of the arc of a radian is equal to the radius of the circle, so a milliradian (mil). So one mil = radius/1000 and .1mil typical scope adjustments = 1/10000 of the radius. The reason it works so well in metrics is that at 100 m 1 mil = 10cm, .1mil=1cm. It's not that the mil is metric, it just works with it. At 100 yards a mil = .1 yds or 3.6" and .1mil = .36" The reason that MOA sort of (but not quite) works with yards is the 36" in a yard and 360degrees in a circle relationship.

At 486 meters a mil = .486m (48.6cm) so .1mil = 4.86 cm.

at 486 yds a mil = .486 yds and .1mil=.0486yds or 1.75"

How much is ½ MOA at 486 yds or meters?

If you think about it and run some numbers you begin to see that thinking in mils is actually pretty easy, you just have to get used to it, and it's way easier than MOA.

[edit] the hard part for me is that I shoot a lot of NRA competitions and I think of windage corrections in MOA. When I look out there and see what looks like about 12MPH blowing at ~½ value I think I think that about 3½ - 4 MOA of wind at 1000 with my 308. I would have to do math to think that though in mils.

 

[sscoyote]

Couldn't help but comment on this. I have put a lot of research into subtension over the years. When I 1st saw the mil-ranging formula expressed as above with the 27.8 factor in it I started wondering where it came from. As it turns out it is simply the ratio of the subtension value (3.6") to the yardage the subtension is measured at (100). This really was an epiphany for me since it begged the question of whether I could use any "subtension unit" in the formula and the answer was yes. From mil-dots to MOA to iron sights and even archery sight pins the formula is the same just with a different subtension unit value. The most basic version of the formula is tgt. size x range of reticle subtension measurement/reticle subtension/"mil-reading" = range. And as it turns out it also defines downrange zeroing as well, since if you think about it a bullet drop value at any distance is the same sort of dimension as a tgt. size. Fun stuff to play with and a full understanding of the concepts can give you a lot of information, and can lead you on a fascinating path of discovery...at least it did for me.

 

[varget204]

1 mil = 3.6" at one hundred yards,at 1000 yards,1 mil = 36" at 486 yards,1 mil =17.496" at 486 yards .1 mil [1/10th] at 486 yds = 1.7496"

 

[jamesdmock]

Mildots are metric and moa is imperial.

The conversion math is a headache. Best is to have the reticle and turrets in the same measurement.

One is not better than the other. Just different scales.

I wouldn't say that milliradians is metric nor empirical. Since it is another way to measure angles, it is neither (or both) metric and empirical. Some find that since the radius of the circle is the unit used, they can estimate distance easier. I prefer MOA and use the ~1" per 100 yards (actual MOA = 1.047"). With a MOA reticle and adjustments in 1/8 MOA, one can look at the target and determine the number of MOA and click 8 clicks for each one. Good shooting...James Mock