MOA - Minute of Angle explained

360° : 360 = 1°

1° : 60 (Minute) = 1 MOA

The definition of minute of arc, or minute of angle, is a unit of angular measurement equal to 1/60th of a degree. This results in a very precise adjustability for scopes with MOA subdivision. Rifle scopes are available with adjustment turrets in 1 MOA, 1/2 MOA, 1/4 MOA and the particularly fine 1/8 MOA subdivision [adjustment per click]. For example, 1/4 MOA scopes have an adjustment of 7.3 mm per click at 100 m and 1/8 MOA scopes have an adjustment of 3.6 mm per click at 100 m.

Distance | Adjustment per click with 1/8 MOA subdivision

1000 m | 36,4 mm

900 m | 32,7 mm

800 m | 29,1 mm

700 m | 25,5 mm

600 m | 21,8 mm

500 m | 18,2 mm

400 m | 14,5 mm

300 m | 10,9 mm

200 m | 7,3 mm

100m | 3,6 mm

Distance | Adjustment per click with 1/4 MOA subdivision

1000 m | 72,7 mm

900 m | 65,5 mm

800 m | 58,2 mm

700 m | 50,9 mm

600 m | 43,6 mm

500 m | 36,4 mm

400 m | 29,1 mm

300 m | 21,8 mm

200 m | 14,5 mm

100m | 7,3 mm

The MOA subdivision is therefore even finer than the MRAD subdivision [0.1 MRAD = 10 mm adjustment at 100 m distance]. However, the subdivision is irrelevant for most shooters, the advantage of the MRAD subdivision lies in the easy calculation of distances to the target and for calculating the dimensions of a target with the scope.

The line of fire deviates from the line of sight, and this becomes more and more evident as the distance to the target increases. Especially Lond Range shooters who shoot at different distances with one setup like to use the MRAD subdivision as well as the military. Rangefinders and night vision technology also work with the meter unit. Most tactical reticles, such as the BDC and MilDot reticles, are also based on the metric system. An explanation of the MRAD subdivision can be found here.