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Not to be confused with Minute and second of arc.
"Millirad" redirects here. Not to be confused with Millirad (radiation unit).
Milliradian
The PSO-1 reticle in a Dragunov sniper rifle has markings with 1-mrad spacing, which can be used to compensate for wind drift, impact correction or range estimation.
General information
Unit system
SI derived unit
Unit of
Angle
Symbol
mrad, mil
Named after
The metric prefix milli- (from Latin mille meaning "one thousand") and the radian
In units
Dimensionless with an arc length one thousandth of the radius, i.e. 1 mm/m or 1 m/km
Conversions
1 mrad in ...
... is equal to ...
radians
1/1000 rad
turns
1/2000π turn
gons
1/5π ≈ 0.063662g
degrees
9/50π ≈ 0.057296°
arcminutes
54/5π ≈ 3.4377′
A milliradian (SI-symbol mrad, sometimes also abbreviated mil) is an SI derived unit for angular measurement which is defined as a thousandth of a radian (0.001 radian). Milliradians are used in adjustment of firearm sights by adjusting the angle of the sight compared to the barrel (up, down, left, or right). Milliradians are also used for comparing shot groupings, or to compare the difficulty of hitting different sized shooting targets at different distances. When using a scope with both mrad adjustment and a reticle with mrad markings (called an "mrad/mrad scope"), the shooter can use the reticle as a ruler to count the number of mrads a shot was off-target, which directly translates to the sight adjustment needed to hit the target with a follow-up shot. Optics with mrad markings in the reticle can also be used to make a range estimation of a known size target, or vice versa, to determine a target size if the distance is known, a practice called "milling".
Milliradians are generally used for very small angles, which allows for very accurate mathematical approximations to more easily calculate with direct proportions, back and forth between the angular separation observed in an optic, linear subtension on target, and range. In such applications it is useful to use a unit for target size that is a thousandth of the unit for range, for instance by using the metric units millimeters for target size and meters for range. This coincides with the definition of the milliradian where the arc length is defined as 1/1,000 of the radius. A common adjustment value in firearm sights is 1 cm at 100 meters which equals 10 mm/100 m = 1/10 mrad.
The true definition of a milliradian is based on a unit circle with a radius of one and an arc divided into 1,000 mrad per radian, hence 2,000 π or approximately 6,283.185 milliradians in one turn, and rifle scope adjustments and reticles are calibrated to this definition.[1] There are also other definitions used for land mapping and artillery which are rounded to more easily be divided into smaller parts for use with compasses, which are then often referred to as "mils", "lines", or similar. For instance there are artillery sights and compasses with 6,400 NATO mils, 6,000 Warsaw Pact mils or 6,300 Swedish "streck" per turn instead of 360° or 2π radians, achieving higher resolution than a 360° compass while also being easier to divide into parts than if true milliradians were used.
^"How to use milliradian-adjustable scopes". Outdoor Hub. 14 July 2011.
A milliradian (SI-symbol mrad, sometimes also abbreviated mil) is an SI derived unit for angular measurement which is defined as a thousandth of a radian...
right Another common system of measurement in firearm scopes is the milliradian (mrad). Zeroing an mrad based scope is easy for users familiar with base...
with radians. A milliradian (mrad) is a thousandth of a radian (0.001 rad), i.e. 1 rad = 103 mrad. There are 2π × 1000 milliradians (≈ 6283.185 mrad)...
can refer to: Mil, singular of Mils Mils, a unit of angle based on the milliradian Mils (artist), a French electronic band Mils, Austria, a town in the...
subdivided into four quarter points, so one turn equals 128. milliradian 2000π ≈0.057° The true milliradian is defined as a thousandth of a radian, which means...
competitors shot placement Spotting scope on its tripod Aircraft periscope Milliradian, an angular measurement used in reticled scopes intended for precision...
volume Millimetre (SI-symbol mm, informally "mil" or “mill”), a length Milliradian (SI-symbol mrad, informally "mil", or three slightly different non-SI...
in milliradians (mrad) and minutes of angle (MOA), which both are angular measurements, making them handy units to use in ballistics. Milliradians are...
= 0.0005067 mm2 (7.854×10−7 sq in) = π/4 square mil angular mil ≈ 1 milliradian ≈ 0.057296 degrees (also known as NATO mil) In areas of machining where...
the telescopic sight features more conventional click adjustments in milliradian increments. The design turned out to be so successful and in demand that...
the gon is rarely used. Angular frequency – Rate of change of angle Milliradian – Angular measurement, thousandth of a radian (primarily military use)...
Often that measurement is converted into angular measurements such as milliradians ("mils" or "mrads") or minutes of angle (MOAs), which expresses the size...
electromagnetic waves always enter good conductors in a direction that is within a milliradian of normal to the surface, regardless of the angle of incidence. In the...
and are designed to provide a usable size of the hit zone of about 1.5 milliradians (or 5 minutes of arc). Cut cardboard targets of the same shape and sizes...
The divergence of high-quality laser beams is commonly less than 1 milliradian (3.4 arcmin), and can be much less for large-diameter beams. Laser diodes...
Milling, a stage in Fulling, a woollen clothmaking process Milling, using milliradian marks to determine range Pavement milling, removing the surface of a...
mil dot spacing change. The USMC standard is that 1 mil (that is, 1 milliradian) equals 3.438 MOA (minute of arc, or, equivalently, minute of angle)...
five to seven rounds, the same as the M2HB. Dispersion: Less than 1.1 milliradian, one sigma radius. Range: Lethal and suppressive out to 2,000 meters...
an infrared image scanning television system with a resolution of 1 milliradian to study the Moon's surface, an ionization chamber to measure radiation...
guidance systems are not perfect and Apollo system drifted about one milliradian per hour. Thus it was necessary to realign the inertial platform periodically...
R ′ = R cos δ A {\displaystyle R'=R\cos \delta _{A}} (see Figure). Milliradian Gradian Hour angle Central angle Angle of rotation Angular diameter Angular...
pulse repetition less than one kHz with beam divergence less than 5 milliradians. Vehicle registration plates are an important part of traffic enforcement...
a setting range from 0 to 10 instead of 0 to 11 symbolizing the 11.2 milliradian elevation adjustment range shown in the current Carl Zeiss Optronics...
assault rifle is usually capable of between 3–6 minute of angle (1–2 milliradian) accuracy. A standard-issue military sniper rifle is typically capable...
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