Heres the link (for those of you who can get to M14 Firing Line Public Forum): http://www.m-14forum.com/upload/showthread.php?t=45017
Here's the question:
M.O.A question
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Alright, got a question about MOA. I have read up some on the term and it's uses and misuses but I have missed one important issue.
Is there a certain range associated with MOA? For instance, if you are shooting 1/2" MOA is that/should that be at 100 yards? Or is the term just used to refer to your group spread at any distance?
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Here's a couple of the answers:
It is stated at a specified distance.
You should fire groups of shots, say 3 at a time, from a rest at a target 100 yards downrange and move your rear sight in 1/2 MOA increments after each group, repeating for several groups on either side of mechanical zero. Use of a scope would make things more precise but isn't necessary. This will tell you exactly how much movement on target you get for a given amount of rear sight adjustment.
If someone says they're shooting "sub MOA" they mean that it is possible to find a point on the target, draw a circle with a radius corresponding to 1 MOA (based on the distance to the target), and the center point for each of their shots would fall inside that circle. That's radius, not diameter. So shooting 1 MOA means your shots are all inside a 2" diameter circle at 100 yards.
I just posted an answer over there that cuts through some of the BS being spread.
For a bunch of pikers that can't respond to Appleseed, they sure could use it.
Well, I guess I have learned something here today: I thought 1 MOA meant the shots would all be inside a 1" circle at 100 yards.
Nope counselor, it isn't. It's just an angular measurement. 1/60th of 1 degree is 1 MOA. Simple, isn't it?
Now, if you were to say "1 MOA accuracy at (x) yards", then yes, you would be right.
A "minute" in angular measurement is 1/60th of a degree. At 100 yrds, it's 1.047 inches, for all practical purposes, an inch.
A circle consists of 360 degrees. Each degree consists of 60 "minutes." Each minute consists of 60 "seconds."
Here are some diagrams, from the "instructor resources" section, not available to everybody. So now they are.
A circle is divided into 360 degrees. Dig out your trig tables, or just trust me. A degree covers, at 100 yards, just over five feet. Or just over 60 inches. That'll come in handy, real soon.
Like an hour of time is divided into 60 minutes, a degree of angle is divided into 60 minutes. So a minute of angle spreads out to just barely over an inch at 100 yards. And just a bit over that at 100 meters. Close enough that we can consider them the same, at least at short range shooting distances.
The "Rifleman's Standard" is to shoot a group of shots no wider than four minutes, from field positions.
See the atttachments. Hope they make it clearer, rather than muddier.