The official definition of MOA, or minute of arc, is that it's a unit of angular measurement, equal to 1/60 of a degree.
1 MOA at 100 yards subtends to 1.04719756 inches if you wanted to be exact. It's rounded off to 1" at 100 yards, or 1" for every 100 yards. A 1 MOA rifle at 100 yards will shoot into approximately a 1" group. A 1 MOA rifle at 200 yards is 2", 1 MOA at 300 yards is 3", and so on.
April 15, 2007, 10:36 AM
What is MOA
A term used way too often to describe rifles that are nowhere near.;)
Quintin gave the correct technical definition.
April 15, 2007, 10:43 AM
Many thanks! I think I got it now. I can shoot one shot groups all day at that! :)
April 15, 2007, 10:46 AM
My understanding is it computes to just a hair over one inch at 100 yards. I've found that more people get 1" groups at 100 yards with a keyboard than a rifle:D
April 15, 2007, 10:49 AM
And, yes, just fractionally off 1"@100 yds.
April 15, 2007, 11:00 AM
Oh yeah, MOA also applies to some scope and sight adjustments.
For sake of ease, let's say you're shooting a rifle with iron sights that have 1 MOA windage and elevation adjustments at 100 yards. Maintaining the same point of aim after you've zeroed the rifle, a one MOA or minute elevation click up will (should) shift the bullet's impact 1" up. A one MOA or minute windage click left or right will (should) shift the bullet's impact 1" left or right accordingly. I say "should," because some sights and scopes adjustments aren't exactly true.
This varies of course depending on the sights or scope you're using - some sights and most scopes have adjustments finer than 1 MOA. A sight or scope that has 1/4 MOA adjustments for windage and elevation will result in a .25" change in the bullet's strike at 100 yards depending on which way you're cranking on those dials.
April 15, 2007, 04:08 PM
Just to expand on what Quintin said, do not equate "one click" of sight adjustment with "One MOA." That may be true on some particular rifle, but usually clicks are finer than that.
April 15, 2007, 04:28 PM
Most scopes are advertised as having 1/4 MOA adjustments.
If you enjoyed reading about "Define MOA" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!