Posted: 12/10/2008 3:32:08 PM EDT
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I wrote a second edition of a paper I originally wrote a while back on mils and moa and their range estimation equations. It should explain everything you always wanted to know about them in a simplified manner. I also have a more detailed paper you can read as well that has more in depth math on the subject. I hope you enjoy and learn.
mils and moa link or mils and moa link and a more in depth paper at: mils and moa in depth Bob "Bags" Simeone |
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I thought there was 6400 mils in a circle. That was what I was taught in the .mil in regards to targeting. (not sniping). I explain that in the more in depth paper (third link down on page 2). That is not correct for American shooters. Our mil is based on 6283.2. The 6400 is generally an artillery and Naval gunfire mil. Bob |
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I thought there was 6400 mils in a circle. That was what I was taught in the .mil in regards to targeting. (not sniping). I explain that in the more in depth paper (third link down on page 2). That is not correct for American shooters. Our mil is based on 6283.2. The 6400 is generally an artillery and Naval gunfire mil. Bob yup. havent read the paper yet, but as it was explained to me, an arty mil is 1 meter at 1 kilometer. the 6283.2 may be the imperial version. |
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I thought there was 6400 mils in a circle. That was what I was taught in the .mil in regards to targeting. (not sniping). Want to make it even easier to understand? Drop the math where you talk about how many radians are in a circle as all you need is ONE radian to work with for people to understand this concept. There is a big difference between artillery mils that may have had some correction to make it easier to relate between imperial and metric. Shooter mils, atleast how they relate to the mil-dot reticle and how they've been used for years, are straight mathmatical trig/pre-calc based measures with simple radians. Screw how many radians or mils in a circle it's almost entirely USELESS as a shooter to sit there and deal with a full circle if you've dealt with radian measure enough. The trig angle of dispersion concept simply doesn't require you to know a full circle and it's easier to simply deal with the math of one radian. Just focus on the principle of what a Radian is and deal with that, it's right there in the article as to what a radian is. Know what your arc of swing about the circumrence of the radian is and that it's equal to your radius(base line you're shooting along from muzzle to target). Devide by 1000 and you've got a mil value at whatever range you are shooting at. At 100 yards you've got 3600 inches you are dealing with from muzzle to target. Using the term mil you are dealing with 1/1000 of that, taking 1/1000 of a 3600 inch arc you wind up with a much smaller nice cute little arc of 3.6 inches at 100 yards. Super easy and the math is correct. No need to really even bother with the tangent/sin/cos functions if you're trying to get the value of what a mil-radian is at 100 yards. Now if you're trying to range in mils you might be doing a little bit of math but it breaks down so simply that you are essentially using ratios. From there it gets pretty easy to figure out for distances knowing that you've got an angle of dispersion. As for actual Trig "math" where you're dealing with a sin/tan/cos function, I have only ever used it when dealing with MOA and nets that 1.047 inches at 100 yards... There are MOA based reticles out there for ranging and it's finally becoming popular to keep elevation/windage adjustments matched to the reticle measurements, Mil turrets for Mil reticle or MOA turrets for MOA reticle but they are mainly on higher dollar scopes. My suggestion? Drop the explanation of how many radians in a circle, it's not really needed. Whether it's trying to find a mil at 1000 yards or a mil at 1000 meters, using one radian and deviding will net you the same results if you know what units you're dealing with. |
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I thought there was 6400 mils in a circle. That was what I was taught in the .mil in regards to targeting. (not sniping). That's the NATO standard. Other armies have different numbers, for exampe I believe the Russians went with 6,000 to keep it simple, and Finland went for accuracy with 6,200 as it's the closest 'easy' number to 2,000xPi. Think about it. Given that the definition of a mil is the arc delineated by an object one unit in length when viewed at a distance of 1,000units, wouldn't it be a hell of a coincidence for the number of such arcs in a full circle is a nice, easy, round number? NTM |
Besides pricing considerations, why the hell would anybody buy a scope where the unit of measure is not the same (ie. MOA reticule with MOA clicks, MIL reticule with cm clicks). Mixing the two is  ETA: OP, thanks for the post. I could have used this information to help a few friends learn this stuff. Saved to my hard drive. Much appreciated. |
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Besides pricing considerations, why the hell would anybody buy a scope where the unit of measure is not the same (ie. MOA reticule with MOA clicks, MIL reticule with cm clicks). Mixing the two is
It doesn't make much sense but in practice 90% of the scopes you find out there that have a mildot reticle will have MOA turrets. Only a few offer Mil/Mil or MOA/MOA combinations and they are usually higher dollar semi-custom offerings. It's strange in that I guess I've become accustomed to thinking of windage and come ups as MOA adjustments but calling range estimations in Mils. I know one of these days if I ever take a precision rifle class it could be interesting working with a spotter if we start talking mils instead of MOA. |
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Quoted: Quoted: Besides pricing considerations, why the hell would anybody buy a scope where the unit of measure is not the same (ie. MOA reticule with MOA clicks, MIL reticule with cm clicks). Mixing the two is It doesn't make much sense but in practice 90% of the scopes you find out there that have a mildot reticle will have MOA turrets. Only a few offer Mil/Mil or MOA/MOA combinations and they are usually higher dollar semi-custom offerings. It's strange in that I guess I've become accustomed to thinking of windage and come ups as MOA adjustments but calling range estimations in Mils. I know one of these days if I ever take a precision rifle class it could be interesting working with a spotter if we start talking mils instead of MOA. That's my point, WTF with the need for conversion, again besides the huge economic investment required to get matching units of measure. Mil reticle..cm click....range in cm using your mil dot...adjust and fire. Same with MOA and inch clicks. Oh well, in this case traditon prevails unless you can fork out 1200+ for an optic. As though it's a technological breakthrough to match up units. |
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A few comments on the above posts:
ZeikHunter: Yes, 1 mil at 1 kilometer (1000 meters) does equal 1 meter. That is based on the true circle properties of 6283.2 mils in a circle. Also, because of that property, 1 mil at 1000 yards equals 1 yard. And 1 mil at 1000 inches would equal 1 inch, and so on and so on. So if there were a unit called "boogers", then 1 mil at 1000 "boogers" would equal 1 "booger". If you read the paper you will understand better. I'm not going to get into the math here, but if you were to "artificially" make a circle have 6400 mils in it, then at 1000 units of whatever you are using, the height would actually be .9817 of what it normally is. For example, if you use a circle that has 6400 mils in it, then 1 mil at 1000 yards would equal 35.34 inches in height (35.34 is .9817 of 36 inches, which is 1 yard). "1" mil at 1000 meters in a circle that is divided into 6400 mils would equal 98.17 cm, just shy of 100 cm (which equals 1 meter). Naturally, a circle has 6283.2 miliradians in it. It is a weird number, but so is pie which = 3.14159....etc. That's an inconvenient number, but we can't help the natural way things are. You can divide a circle into whatever divisions you want too to make it easier for you, like 6200, 6400, 6000, etc., but when you do that, you will also screw with the units other ways. I don't want to confuse anybody, so if you are interested, it is in the paper. I will be glad to answer any questions anybody has on the subject, just email me. Thank you. Bob |
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uglygun: I understand your points. This paper is just background for anybody who wants it. You don't need it, but some people like the background.
uglygun and KnobCreek: Yes, it is confusing when you have mils on the reticle and adjust your knobs in moa. From my research on the subject, the reason for that is scopes were originally made for civilians, and the military adopted them for their use. They, the civilian manufactureres, had their adjustments in moa. When the military started using mils for their reticles, the scope manufacturers, who were civilian in there background, said fine, we'll put a mil reticle in there for you, but they still kept their adjustments in moa. Today, many scopes have moa/moa or mil/mil adjustments. I have a Nightforce NSX in moa/moa. Makes it easier I think to keep the units the same. Bob |
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Quoted: Again, thanks for the information you provided and the history/backround. I have the exact same Nightforce optic as you (MOA/MOA), as well as a Horus Vision Falcon(MILS/CM). Love the matched units of measure.uglygun: I understand your points. This paper is just background for anybody who wants it. You don't need it, but some people like the background. uglygun and KnobCreek: Yes, it is confusing when you have mils on the reticle and adjust your knobs in moa. From my research on the subject, the reason for that is scopes were originally made for civilians, and the military adopted them for their use. They, the civilian manufactureres, had their adjustments in moa. When the military started using mils for their reticles, the scope manufacturers, who were civilian in there background, said fine, we'll put a mil reticle in there for you, but they still kept their adjustments in moa. Today, many scopes have moa/moa or mil/mil adjustments. I have a Nightforce NSX in moa/moa. Makes it easier I think to keep the units the same. Bob |
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<––- Teaches radian based trig At one point in time I was considering becoming a math teacher at the highschool level but I actually went back to school to take math classes(precalc through calc III) for furthering my understanding of the shooting world. I didn't really need to go beyond calc I or II but once I got into it I considered going further with it. Then I went and transferred to the 4 year institution dropping back a class to do a course of instruction with the institution and they completely blew me out of the water with how they taught math, I would of had to start completely over again to get the fundamentals they were teaching. Now I'm nothing but a geeky gun enthusiast cop, some co-workers start going when I mention a lot of math along with guns.
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Mildot master FTW! Yes, like I say at the end of my in depth paper (the 3rd link down): "At this point, you can now brain dump most of this math and definition stuff, and just use them like they’ve always been used.....but hopefully with a little better knowledge". Bags |
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<––- Teaches radian based trig At one point in time I was considering becoming a math teacher at the highschool level but I actually went back to school to take math classes(precalc through calc III) for furthering my understanding of the shooting world. I didn't really need to go beyond calc I or II but once I got into it I considered going further with it. Then I went and transferred to the 4 year institution dropping back a class to do a course of instruction with the institution and they completely blew me out of the water with how they taught math, I would of had to start completely over again to get the fundamentals they were teaching. Now I'm nothing but a geeky gun enthusiast cop, some co-workers start going when I mention a lot of math along with guns.
I was a mth major at Umass (1985) and really this is the first time I used it besides helping the kids with homework. Bags |
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Bob
There is only 1 Mil is usage by the US military, it is 1/6400 of circle. It has been in usage since since 1904. The reason 6400 was used by Capt Charles Dapples when he invented the mil back in the late 1800s as an artillery officer was to simplify the math vice using milliradians. Artillerymen have corrected for the change from milliradians to mils by multiplying or dividing by 1.0186 whenever precission measurements were made. What most people refer to as mils are not mils, but milliradians. Not the same unit of measure and it those who should know better still incorrectly say the mils or "milling" a target when they are in fact using milliradians. |
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Bob There is only 1 Mil is usage by the US military, it is 1/6400 of circle. It has been in usage since since 1904. The reason 6400 was used by Capt Charles Dapples when he invented the mil back in the late 1800s as an artillery officer was to simplify the math vice using milliradians. Artillerymen have corrected for the change from milliradians to mils by multiplying or dividing by 1.0186 whenever precission measurements were made. What most people refer to as mils are not mils, but milliradians. Not the same unit of measure and it those who should know better still incorrectly say the mils or "milling" a target when they are in fact using milliradians. From another forum on another website. I've had this argument befroe, "Good effort. I have a couple of recommendations. A milliradian and an MOA are angles, both of which have precise derivations, as you noted. It's simply confusing to use the same terms for units which are not quite the same. Therefore, in your paper, I recommend that you do the following: (1) Completely delete all references to the mil based on 6400 per 360 degrees. They are never used in sniper optics, at least in the U.S. and Europe, and so there is no reason to add the complexity of dealing with them in an already complex subject." link Bags |
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Do you understand by all us military references that if you refer to a mil, you are in fact referring an angular measurement in which the a circle is subdivided into 6400 equal increments?
Even in aircraft manuals when they refer to the mils displayed in Pipers, etc it is in the same mil as everyone else uses. The angles the are referring to are not mils, they are milliradians. They are being lazy by using an already existing and define measure and mis-defining it to save 5 syllables. If Mils had not existed previously, than it wouldn't be an issue, but you are talking about a unit of measure that have been used by the US military since 1904 and by nations such as Germany and France since the late 1800s. |
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Do you understand by all us military references that if you refer to a mil, you are in fact referring an angular measurement in which the a circle is subdivided into 6400 equal increments? Even in aircraft manuals when they refer to the mils displayed in Pipers, etc it is in the same mil as everyone else uses. The angles the are referring to are not mils, they are milliradians. They are being lazy by using an already existing and define measure and mis-defining it to save 5 syllables. If Mils had not existed previously, than it wouldn't be an issue, but you are talking about a unit of measure that have been used by the US military since 1904 and by nations such as Germany and France since the late 1800s. Ron, all good points and good history. And I will concede your points. That is great knowledge and not very well known by most. Thank you. My paper is for rifle shooters. Therefore, let me correct myself. For shooters, when we talk about mils, we mean the incorrect verbiage but commonly understood actual mathematical milliradians based on 6283.2 milliradians in a circle and which equals 3.6 inches at 100 yards and is also equal to 3.438 moa at 100 yards. We shouldn't call them mils, but we do. So if talking to other shooters, that is fine. If talking to an artillery guy or some old French guy, make sure you say "milliradians. Here is what I wrote in my original in depth paper written last year on the bottom of page 2 (third link down above): There is some controversy out there about what type of “mils” American military and tactical shooters use. Some think they use a mil that is based on a circle that has 6400 mils in it instead of 6283.2. This has widely been circulated, written about and even taught, including in the military. But this is not the case. While it may be true that some Artillery and other military units do use this type of mil (the one based on 6400), American military snipers and tactical shooters use scopes that are based on and calibrated using “real mathematical milliradians”, which are 6283.2 milliradians (mils) per circle. (Note: Some other countries, like Russia for example, do use different types of mils for their scopes, but for American shooters, our “mil” is 6283.2 milliradians per circle). Bags |
| Artillery doesn't think we use a 6400 we know; We have for literally centuries. The Russian system is called the DC system. The reason that 6000 and 6400 were originally used was in the past there were both horse and fortress/foot artillery. Horse artillery use the 6000 system since they only did direct fire and 6000 was accurate enough. Foot and fortress artillery used the system based on 6400 for increased accuracy in computation. |
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This is a perfect example of why we need to scrap the English system and switch to metric.
Or better yet, lets just make it more complicated and add in the "arshin" Russian imperial measurement! (Isn't Arshin also the german word for ass?) If the .Mil can do it so can the civilian populace. THough I do think for the average Knuckle head we'll have to make a special appeal! "Hey there Joe! Say, Your Penis isn't 6 in. it's 15.6 CM!! Now isn't that swell? All thanks to the new Metric system." (Insert picture of 1950's guy sitting in chair with pipe here.) |
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Thanks for posting this. I have just read an article on http://www.snipershide.com/modules.php?name=Content&pa=showpage&pid=30 that promoted the use of mil adjusted scopes and discussed some of the confusion about them as well and I had been on the search for more info.
at least they rounded up to 6283.2, going with 6283.1853071795865 would suck. |