Interesting (one way to describe it) discussion on what MOA means

[Old Dog]

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

--------------------------------------------------------------------------------

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?
__________________

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.

[Nickle]

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.

[Counselor]

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.

[Nickle]

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.

[Burke]

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."

[didactic]

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.