Language Lessons: Minute of Angle (MOA)
Relates to: Measurement(s) and Adjustments
Category: Shooting Terminology
Applications of Use: Shooting, Zeroing, Communicating target size, Accuracy
Definition: MOA is a standard unit of measurement used for adjusting weapon sights and ballistic-related measurements. It is also used to indicate accuracy of a weapon as well as target size.
Minute of Angle is derived from a circle in the following way: a circle has 360 degrees, each degree is further broken down into 60 minutes (visualize a clock). Each minute is an MOA (1/60 of a degree). At a distance of 100 yards, 1 MOA is equal to 1.047”, but most people round it down to 1” at 100, 2” at 200, 3” at 300, and so on.
Here is a great video explanation from Ryan Cleckner:
Why it Matters: The term MOA is used everywhere in the firearms industry, from manufacturers to consumers. It’s used on ranges, at matches, and in online forums. If you don’t know what a Minute of Angle is, you’ll have a hard time not only understanding your weapon system, but also understanding everyone else.
Into the Weeds: MOA is an angular measurement. Angular measurements are used in shooting because bullets don’t shoot in a linear fashion; their trajectory is angular.
We know there are 360 degrees in a circle thanks to early astronomers’ observations that constellations moved each day by a small degree. And 360 days later, the constellations were back at their start point. The astronomers’ conclusions were slightly off since we know there are 365 days in a year (actually 365.242199 degrees in a year to be exact). But, we still use 360 degrees for a circle because ancient math used 360 degrees for a circle and it just works better (mathematically) than using 365.
Though 360 degrees doesn’t initially sound very intuitive, it’s a number that’s easy to half, quarter, and break into thirds–there are 12 inches in a foot and 36 inches in a yard for much the same reason. Analog clocks are also broken down in this way. It doesn’t seem like a big deal now, but before you walked around with a calculator in your pocket 24×7 in the form of an iPhone….
In Summary, MOA is a standard- just a unit of measure. Now you’ll be able to know what it means when someone says “That target was a 3 MOA target at 600 yards,” or “My new gun shoots 1 MOA.”
Question for the Crowd: What accuracy (MOA accuracy) do you expect for your AR15?
Mad Duo, Breach-Bang& CLEAR!
Emergency: Activate firefly, deploy green (or brown) star cluster, get your wank sock out of your ruck and stand by ’til we come get you.