What does MOA means?

[CEIBA]

I am knew to guns and hunting. Recently I came across an article referring to MOA. No description of the term was given. I supposed its assumed that readers know what it means. I have Google it and have searched in many places but can't find an answer.

Thank you for your help.

 

[lilharcher]

Minute of Angle (MOA) | National Shooting Sports Foundation

Took me 15 seconds with Google searching "MOA"

 

[Bart B]

The subtended angle a MOA has was simplified for the shooting sports in the USA over a century ago as 1 inch per hundred yards of range. As all the smallbore and high power rifle targets had then and today have scoring rings based on inch intervals, that made things easy to do. 1 MOA equalled 1/3600th of the range. One inch for every hundred yards of range.

Metallic rear sights made in the USA and some other places for target use had then and still do have 40 tpi threads on their adjustments. One turn move the rear sight .025" and with the standard 30 inch sight radius for 24" barrels, that equated to 3 MOA per turn over 12 clicks. 1/3600th of 30 inches is .00833" and that multiplied by 3 equals .025" 1/4 MOA per click.

Externally adjusted target scope bases had a standard spacing of 7.2 inch. 1/3600th of that equals .002", so with the adjustment threads at 40 tpi and 50 clicks of them for one turn, 4 clicks moved the adjustment .002". Again, one MOA for 4 clicks. 1/4 MOA per click.

In the 1960's folks using their brand new fangled digital calculators learned the sine of 1 MOA of angle was 0.00029088820456342459637429741574.... and that multiplied by 3600 inches in a hundred yards gave 1.047197536428328546947470696664... inch per hundred yards.

Those that insist on perfection and exact stuff never move a 100 yard target with inch spaced scoring rings to about 95 yards so their spacing more closely equals what a trig MOA subtends.

 

[Waynard]

You guys did read the fella is new to hunting and guns, simply put moa is about 1 & 1/4 inch circle at 100 yards.

 

[FEENIX]

I am knew to guns and hunting. Recently I came across an article referring to MOA. No description of the term was given. I supposed its assumed that readers know what it means. I have Google it and have searched in many places but can't find an answer.

Thank you for your help.

CEIBA,

Welcome to LRH and enjoy!

As new member, the custom search on the top right corner is a very useful tool for all your queries.

Cheers!

Ed

 

[Edd]

You guys did read the fella is new to hunting and guns, simply put moa is about 1 & 1/4 inch circle at 100 yards.

I think the number 1.04719758 has confused you. One MOA is slightly less than 1-1/16 inch at 100 yards. 1-1/4 inches would be about 1.2 MOA. It would take about 550 yards to add 1/4" to the measurement.

 

[Mikecr]

OP don't let rounded Inches per hundred yards(IPHY, hunter's MOA) distract you too far from the actual MOA standard.
The .047" added to 1.000" absolutely becomes significant at distance & dialing ~40MOA+.
For example, 750yd shot with 40 IPHY dialed, instead of 40 MOA per ballistic solution.
The 40 dialed would carry an error of .047 x 40 =1.89 IPHY(from actual MOA) x 7.5 = 14.16"
With this much error from nothing more than lack of understanding -you probably shouldn't be taking hunting shots so far.
Groundhogs wouldn't even notice my shots if I did this..

It's generalizations here, especially in merchandising, that has led to most scopes not actually dialing in true MOA(even while advertised as 1/4moa adjustment, etc.). So we counter by testing our scopes to discover their true IPHY per click and entering this in our ballistic software.
Only when each '1/4moa click' actually measures 0.262" at 100yds, do we enter 1/4moa per click.

This is a LR hunting site, and not a competition shooting site.
As LR hunters we're not bound by arbitrary and fixed standards. We must account for realities in our capabilities.
Another example; in group measure IBS subtracts cal from group diameter. That is, they subtract .243" from a group shot with a 6mm. This is dead wrong, they should be subtracting a 6mm bullet hole, produced by that target paper, from group diameter. Try it sometime, it's a significant difference,, then consider all the 'world records' that have been recorded inaccurately.

 

[Trickymissfit]

The subtended angle a MOA has was simplified for the shooting sports in the USA over a century ago as 1 inch per hundred yards of range. As all the smallbore and high power rifle targets had then and today have scoring rings based on inch intervals, that made things easy to do. 1 MOA equalled 1/3600th of the range. One inch for every hundred yards of range.

Metallic rear sights made in the USA and some other places for target use had then and still do have 40 tpi threads on their adjustments. One turn move the rear sight .025" and with the standard 30 inch sight radius for 24" barrels, that equated to 3 MOA per turn over 12 clicks. 1/3600th of 30 inches is .00833" and that multiplied by 3 equals .025" 1/4 MOA per click.

Externally adjusted target scope bases had a standard spacing of 7.2 inch. 1/3600th of that equals .002", so with the adjustment threads at 40 tpi and 50 clicks of them for one turn, 4 clicks moved the adjustment .002". Again, one MOA for 4 clicks. 1/4 MOA per click.

In the 1960's folks using their brand new fangled digital calculators learned the sine of 1 MOA of angle was 0.00029088820456342459637429741574.... and that multiplied by 3600 inches in a hundred yards gave 1.047197536428328546947470696664... inch per hundred yards.

Those that insist on perfection and exact stuff never move a 100 yard target with inch spaced scoring rings to about 95 yards so their spacing more closely equals what a trig MOA subtends.

dang Bart, I thought I caught you in an error, but you got it right. For all practical purpose a minute of angle is 1.048". Most folks think it's one inch.

Arc minutes, seconds, or I guess even hours are nothing new, and have always been there. We didn't know how to use them a few decades back. Yet other folks used the numbers daily. Astronomers', NASA, and a few very finite machining concepts did. Yet the numbers don't really compare totally with a measurement we normally go by; even though they really do in the end. So when you see the term "Arc" in relationship to measurement, you know it's finite. So when your making measurements in the .000050" and smaller ranges, you normally forget about what we take for granted and speak of arc seconds and so on. (an arc second computes to .000048" in one foot length). This is measured by light refraction, as a laser isn't all that perfect. Yet a low powered light beam is nearly perfect (yes light will bend in an infinite length). Still if you booking a flight to Mars, you pretty much figure they've got everything figured to one thousandth of an arc second just to get you in the neighborhood of the place.
gary

 

[just country]

moa 1.047"

 

[Rich Coyle]

dang Bart, I thought I caught you in an error, but you got it right. For all practical purpose a minute of angle is 1.048". Most folks think it's one inch.

Arc minutes, seconds, or I guess even hours are nothing new, and have always been there. We didn't know how to use them a few decades back.
gary

Fifty years ago I was working in a wood shop. The boss told me the chairlegs needed to be drilled for the stretcher at 5 degrees. I don't remember ever seeing a degree tool so I used minutes of angle and got so close no one noticed I didn't use some kind of tool. I guess I got lucky.

 

[FearNoWind]

Minute of Angle (MOA) | National Shooting Sports Foundation

Minute Of Angle

 

[FearNoWind]

. I have Google it and have searched in many places but can't find an answer.

Thank you for your help.

When you do a Google search for something that's a bit vague (like MOA) try your search using "define ...... ". You'll have greater success.

 

[Waynard]

Merry Christmas!! Fellas!

 

[Bart B]

dang Bart, I thought I caught you in an error, but you got it right. For all practical purpose a minute of angle is 1.048". Most folks think it's one inch.

I still do. But it depends on what one considers "practical."

Few scopes stating MOA adjustments based on mils, trigonometry or inches do so exactly. Their optics' lens tolerances prevent it as sometimes does their mechanics. Which is why one should precisely measure their scope's adjustments. Boxing few-shot groups is not precise. A solid anchored scope and a yard stick or tape measure down range is pretty darned precise. Use a monocular to look through the scope's eyepiece and you can resolve reticule position 7 or so times better.