My husband and I did a little shooting competition of sorts. There is no prize other than bragging rights and if nothing else it got us out of the house and doing some shooting. I posted some pictures of our time out on Facebook describing what we did as well as my average Minute of Angle (MOA).
Then I got to thinking that many have no idea what MOA is. I didn’t until my husband explained it to me.
Minute of Angle or MOA is most simply a unit of measurement used to measure accuracy. In the simplest form 1 MOA is a one inch group of shots at 100 yards distance. 2 MOA is 2 inches at 200 yards. And it goes up from there.
For more detail let’s look at how this is figured.
360 degrees X 60 minutes per degree equals 21,600 minutes in a circle.
The circumference of a circle equals Pi X Diameter or 3.14 X Diameter
Diameter(equals 2X [the radius for a 100 yard MOA] (100 yards X 36 inches)= 7200 inches)
So.. 3.14 X 7200 = 22608 inches around a circle of 200 yards in diameter.
The circumference of 22608/21600 minutes in a circle = 1.047″ subtended by an angle of One minute at a radius of 100 yards.
One Minute of Angle = 1.047″ at 100 yards
One Minute of angle = 5.233″ at 500 yards
One Minute of Angle = 10.47″ at 1000 yards
It is broken down or rounded off if you will into 1 inch at 100 yards and so forth.
Why Is This Important?
If we are being honest, at the end of the day if you are shooting for fun or sport, then it really isn’t important. But sometimes it is a lot of fun for us to add in a little healthy competition. And if you are looking to practice on accuracy, knowing how to figure your minute of angle is useful.
I also really enjoy shooting like this. It forces you to think about absolutely nothing but the shot. How your legs are positioned. How you are breathing. Your trigger pull. It causes everything else around you to go quiet and nothing else is allowed any space in your head except that next shot.
Figuring your minute of angle is then done by taking a group of at least 5 shots at one target. You can then measure from center to center of the 2 furthest shots. Or, you can measure outside ring to outside ring with calipers or tape ruler in inches. You will then subtract the diameter of one bullet.
For example if your shooting a .223 and your 5 shot group measures 1.13″ you will subtract 0.224″ to get a group of 0.906″. If you are shooting a .22lr you will subtract 0.223″, for a 308 you will subtract 0.308″.
At the end of the day my best group was the third target which measured .413 MOA. And overall I ended up with a 1.60 MOA. I am planning to go back out this weekend and beat that!
Now you know how to figure Minute of Angle.