Talk:Milliradian

Use of mils by the US Navy

The phrase:

armies use metric units for mapping and targetting, even the U.S. Army.

was changed to:

armies use metric units for mapping and targeting, even the U.S. Army, but the U.S. Navy does not.

The sentence is talking about army use, so I don't think navy use belongs in the same sentence. The mil is used within the US Navy at least as follows:

• by the USMC just like the US Army
• by the US Navy for fire support of land operations

Bobblewik 12:51, 31 July 2005 (UTC)

The point wasn't about the use of mils; it was about the use of yards. And, more specifically, the old claim was that English units in general are no longer ever used with mils. I claim that is false. Gene Nygaard 12:54, 31 July 2005 (UTC)

In other words, the problem dealt with the clausefor which what you have quoted above was an explanation and justification, namely:

No conversion to Imperial units is provided because [rest of sentence above in first quoted text, removed from second].

Gene Nygaard 13:09, 31 July 2005 (UTC)

I just get it. Thanks. I had been misreading it as armies use mils rather than armies use metric units. Now I think that the whole sentence should be taken out. Bobblewik 13:18, 31 July 2005 (UTC)

Okay by me. Gene Nygaard 13:26, 31 July 2005 (UTC)

Note that if it were converted, "1 mil at 1 km is about 1 metre" it should be "1 mil at 1,000 yards is about 1 yard". Not really necessary, I don't think, and not needing an explanation why it isn't there. Gene Nygaard 13:29, 31 July 2005 (UTC)

Thanks. Copy edited as discussed. Bobblewik 13:45, 31 July 2005 (UTC)

History of the four definitions of the mil

The chapter makes references to Soviet Union and NATO, however, obviously the concept of angular mil is older than WWII (and likely also older than Soviet Union), some historical perspective would be useful, i.e. when the different definitions in fact have emerged. --Sivullinen (talk) 12:16, 4 August 2008 (UTC)

Defining the milliradian

Instead of clearly defining a mil, the article makes a reference to its section with the number of mils in a full circle in various parts of the world, e.g. 6400 within NATO. While on the surface it makes sense, it is no good. The problem is that the defining characteristic if the angular mil lies in its name (meaning thousand), i.e. it is the angle one looks into when observing an object with a size 1000 times smaller than its distance. If the mil was actually defined so 6400 mils equals a full circle, the relation between subtension on target [in meters], distance [in km] and observed angle of view [in mil] would not be the familiar

${\text{distance}}={\frac {\text{subtension}}{\text{angle}}}$

, but rather something that with an accuracy of 7 digits would spuriously be

${\text{distance}}={\frac {\text{subtension}}{\text{angle}}}{\frac {2000\cdot \pi }{\text{6400}}}$ (in the case of NATO). (7 digits because 1e-8 < (2 * Arcsin(0.5/1000)-1e-3)/1e-3 < 1e-7).

I posit that this spurious correction (of 1.86% for NATO, 6400/(2000$\pi$) - 1) is _not_ part of the angular mil definition (at least not in NATO nor in the Armed Forces of the Russian Federation) and that therefore the whole article is fundamentally flawed.

To fix this we just need a WP:RS with an actual definition (which I suspect will base itself on the D = S / V property, but what I suspect does not really matter). Would there not be a Wikipedian out there with a field manual that we can quote? Lklundin (talk) 22:39, 25 February 2015 (UTC)

Hi, the article has been updated a lot since your comment was written, so I think this should be clear now. There has formerly been some confusion in the shooting community whether the mil is based on a circle with 2000 Pi ≈ 6283.185.., 6400, 6000 or 6300 milliradians. But a milliradian is mathematically defined as a thousandth of a radian, so the first of ≈6283 mil per circle is the one that is correct. This is based on the definition of the radian and the metric prefix "milli". Sauer202 (talk) 15:38, 25 October 2017 (UTC)

What is a subtension?

Because the word subtension isn't in most dictionaries, it would be a good idea to define it here if it is going to be used in the article. — Preceding unsigned comment added by 172.78.86.54 (talk) 15:40, 20 October 2017 (UTC)

Hi, and thanks for the suggestion. Subtension refers to the length between two points on a target. For a given angular distance (or angular diameter) the subtension will vary with viewing distance to the target. In shooting the units for angular measurement will typically be given in either milliradians or minutes of arc, while the subtension on target will be given in centimeters, millimeters or inches. For instance 0.1 mil will subtend 1 cm at 100 meters, 2 cm at 200 meters, etc. I've added this explanaition in the article. Sauer202 (talk) 15:00, 25 October 2017 (UTC)

Ballistic table in the Sight adjustment section

An illustrative table has been uploaded by a user, I think called 'Sauer202'. It is a ballistic table for 7.62x51mm NATO ammunition.

Looking at the version history they have corrected some errors, but I believe as at this time it still contains errors (and its listed as their own work). I think they need to be more careful when providing data tables to illustrate articles.

As you can see from a different table further down this article (which I believe to be correct) in the 'Mixing mrad and minutes of arc' section, there is a ratio between 1/4 MOA click and milliradians of 0.073, and thus with tenth-milliradians of 0.73. The ballistic table uploaded by user Sauer202 respects this ratio between its '0.1 mil clicks to correct' and its '0.25 MOA clicks to correct' columns until the '600m' row, whereupon it deviates from this 0.73 ratio until the final '1000m' row where it respects this ratio again. Since tenth-milliradians and 1/4 MOA clicks are both units of angle (measurement of the same underlying type of quantity) I don't think this variation should occur, and leads me to believe the table still contains errors. — Preceding unsigned comment added by 79.68.216.228 (talk) 16:52, 15 November 2021 (UTC)

Hello, thanks for the feedback. I've corrected the MOA line at 700 meters from 23.25 MOA to 22.25 MOA, and 93 clicks to 89 clicks. I could not find any other errors. I guess that the confusion around the 700, 800 and 900 meter values stem from that there naturally will be some rounding errors from drop value in centimeters to the "stepped" click values in a ballistic table due to sampling.

For example, with a 675 cm drop at 800 meters (which is still unchanged in the new version), this corresponds to:

• 6750 mm / 800 m = 8.4375 mrad drop -> which has to be rounded down to 8.4 mrad or 84 clicks on a 0.1 mrad turret.
• 8.4375 mrad * 3.4377 ≈ 29 MOA drop or 116 clicks on a 1/4 MOA turret, so no rounding needed in that case.

This gives a ratio of 84/116 = 0.724137931, different to ~0.727230415.. which is the true ratio between 1/4 MOA and 0.1 mrad.

Or with a 966 cm drop at 900 meters (which is still unchanged in the new version), this corresponds to:

• 9660 mm / 900 m = 10.7333333 mrad drop -> which has to be rounded down to 10.7 mrad or 107 clicks on a 0.1 mrad turret.
• 10.7333333 mrad * 3.4377 = 36.8979799 MOA drop -> which has to be rounded up to 148 clicks on a 1/4 MOA turret.

This gives a ratio of 107/148 = 0.722972973, which is also different to ~0.727230415.. which is the true ratio between 1/4 MOA and 0.1 mrad.

If I've understood the concern right, I want to sum it up like this: The table does not describe the relationship between milliradians and arcminutes as units, but rather a practical application using rounded numbers with finite resolution on two different scales. Sauer202 (talk) 17:54, 28 July 2022 (UTC)

Approximation error

Not sure where to put this, but the Approximation error section had a bad formula to calculate the error for MOA/inches per hundred yards. I've corrected the formula and the resulting approximate errors, but didn't touch the footnotes. Are they necessary if the formula's already provided? — Preceding unsigned comment added by 96.241.126.122 (talk) 23:51, 15 November 2021 (UTC)

Split artillery mils

With the war in Ukraine, there were discussions looking at the use of NATO artillery where people did wrongly assume they would use Gradian for aiming. The definition of the artillery mil was not found - as it is hidden behind the Milliradian topic.

In de/es/fr wikipedia there are two articles for milliradian and artillery mils. I propose to do the same in en-wiki which would also be a good idea as this article here is quite long already. Guidod (talk) 09:36, 5 January 2023 (UTC)