Quote Originally Posted by zephyr View Post
How does the MRAD of the Compact compare to the MOA of the 30SF in relation to the Mildots? Does it only matter if you compensate with 'clicks' instead of holdover?

Does anyone have both the Compact and 30SF? How do the lenses compare? I have the 30SF and the lighter weight of the Compact would be a plus.
Milliradians, (MRAD or Mil) and Minute of Angle, (MOA) Trivia
(Best with a 6 pack of BUD)

Formula for circumference of a circle = Diameter, (D) x Pi, (Pi = 3.14159.)
There are 7200” in (D) diameter of a 100 yard circle. (100 x 36” x 2 = 7200”)
Circumference of a circle at 100 yards = 22,619.448”, (7200” x 3.14159 Pi.)
1 MRAD & 1 MOA is an angular measurement at a specific distance or range.
6,283.185 Milliradians (MRAD) = 1 CIRCLE (Pi 3.14159 x 2 x 1000 = 6,283.185, mathematical.)
6,400 Milliradians = 1 CIRCLE, (NATO rounded MRAD.)
21,600 Minutes = 1 CIRCLE, (360 degrees x 60 Minutes in 1 degree = 21,600 minutes)
1 MOA = 1.0471975” at 100 yards, 22,619.448”/21,600 Minutes, (1” rounded.)
1 MRAD = 3.6” at 100 yards, 22,619.448”/6283.185 MRAD, mathematical.
1 MRAD = 3.534” at 100 yards, 22,619.448/6400 MRAD, NATO.
1 MRAD = 10 cm at 100 meters. (2 x PI x 1000 = 6283.185 MRADs in a circle). 100 meters = 10,000 cm x 2 = 20,000 cm in diameter of 100 meter circle. 20K x PI = 62,831.85/6,283.18 MRADs = 10 cm; for (1 MRAD at 100 meters = 10 centimeters).
Scope settings MOA or MRAD.
It also depends on what your scope's notion of 1 milliradian is, because the NATO milliradian differs from the mathematical definition of a milliradian.

A mathematically accurate radian is that part of a circle where 2 * PI radians is a full circle, and a milliradian, (MRAD), is 1/1000th of a radian, so a full circle is equal to approximately 6283.185 milliradians (2000 * PI).
But the NATO definition of a milliradian for use in ballistics is that a full circle is split into 6400 NATO milliradians.

Anyway, the difference is not very large, with mathematically accurate MRADs, 1 MRAD is 100 cm @ 1000 m, with 1 NATO MRAD, it is 98.2 cm @ 1000 m. For this reason, if your scope uses mathematically accurate MRADs, 1 MRAD is about 3.44 MOAs, but if it uses NATO MRADs, then 1 MRAD is 3.375 MOAs.
 
The distance of the reticle's movement per click is tan(angle) * distance, however, at longer distances this is not exactly equal to the change in point of impact, because of the difference between changes to the line of sight and changes in the bullet's trajectory.

degrees = MOAs / 60
MOAs = degrees * 60

degrees = MRADs / (PI * 1000) * 180
degrees = (MRADs / 6400) * 360 [with NATO MRADs]
MRADs = (degrees / 180) * PI * 1000
MRADs = (degrees / 360) * 6400 [with NATO MRADs]

MOAs = MRADs / (PI * 1000) * 10800
MOAs = (MRADs / 6400) * 21600 [with NATO MRADs]
MRADs = (MOAs / 10800) * PI * 1000
MRADs = (MOAs / 21600) * 6400 [with NATO MRADs]