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Old November 13, 2002, 04:06 PM   #1
yzguy
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Moa ??

ok I looked up MOA and see it stands for minute of angle, but what exactly does that mean? (if I see .5 MOA or something, what does that mean)
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Old November 13, 2002, 04:14 PM   #2
Mal H
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Some very good explanations can be found here: http://www.thefiringline.com/forums/...threadid=51703
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Old November 13, 2002, 04:26 PM   #3
Jody Hudson
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I minute of angle. That is 1/60 of 1 degree of angle from the viewpoint of the shooting position -- regarding the spread from one far side to the other far side of a group of shots.

1 MOA is roughly equal to a 1 inch diameter group of shots at 100 yards distance; 2 inch diameter group at 200 yards... 10 inch group of shots at 1,000 yards.

This type shooting is done VERY carefully and usually from a very solid bench rest with a good telescopic sight and is usually done with the very best ammo for that particular rifle or pistol.

MOST pistols and rifles do better with one or two types of ammo than with others; the variables being such things as velocity, weight of the bullet, diameter of the bullet, etc.

The very best rifles will shoot 1 MOA or smaller groups with the best ammo for that particular gun.

Just a note here: this is such a difficult feat that two rifles of the exact kind, made in the same factory, with sequential serial numbers -- will shoot differently and will often prefer different ammo as the most accurate ammo.

Also, there are some characteristics of the shooter; with two champion shooters and the same gun there may be differences in accuracy. I personally think this has to do with such things as muscle mass, bone mass, length of arms and such non-changable things in the individual shooters. My son and I shoot against each other several days a week and we have for years. There are some mysteries; some guns just plain hit better for one of us than for the other and those guns stay like that for us from day to day, month to month and year to year.

The quest is to find a gun that shoots very accurately for the individual shooter; this is easiest done with the best (not necessarily the most expensive) guns. Then the individual shooter, while perfecting his skills, chooses the ammo that is best for HIMSELF and that may not be the best ammo for the next shooter of that gun in every case.

You can purchase a several thousand dollar rifle that is guaranteed accurate to 1/2 MOA with a certain exact ammo -- and it was made to survive that guarantee. However, it is possible that you can pick up an old Mauser or Remington or a new CZ or Marlin or Savage and shoot just as well or better for a couple of hundred dollars or less -- with the best ammo for you and that gun.

Have fun learning how to shoot less than ONE MOA... it is a fun quest and difficult to do. We call that shooting Sub MOA; that is less than one MOA.
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Old November 13, 2002, 05:40 PM   #4
dZ
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this is a moa
Attached Images
File Type: jpg pb-moa.jpg (31.4 KB, 201 views)
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Old November 13, 2002, 08:34 PM   #5
Dave R
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<wiping stuff off my monitor>

Yes, that certainly is a Moa. Not be confused with MOA.
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Old November 13, 2002, 08:56 PM   #6
WIL TERRY
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Let me think....okay, a MINUTE OF ANGLE is

1.047" at 100 yards...
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Old November 14, 2002, 01:00 AM   #7
Chuck Dye
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On your scientific calculator, group size in minutes of angle is arctan D/R where D=group size and R=range. D and R must be in the same units. Your calculator will give the answer in decimal degrees which must be multiplied by 60 to yield MOA. Thus, a 1 inch group at 100 yards is (arctan1/3600)x60=0.9549MOA. Arctan or arctangent is probably tan to the -1 on your calculator, but I have yet to find a way to write exponents in this forum.

Don't forget that the standard for measuring groups is center-to-center. That is most easily obtained by measuring from the farthest most edges of the two most widely spread shots and subtracting the bullet diameter. A friend had been shooting 1 inch groups, outside edge to outside edge. Pleased with such accuracy, he was absolutely delighted when I gave him an instant 26% improvement in his (measured) accuracy!
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Old November 14, 2002, 07:24 AM   #8
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And I'll just throw in that each MOA is divided in into Seconds of Angle. Yep, just like a clock... 60 seconds in a Minute, 60 minutes in a degree*. So a .5 MOA group is actually 30 SOA and a 1" group approx 57 SOA.

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Old November 14, 2002, 07:24 AM   #9
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Huck - "... but I have yet to find a way to write exponents in this forum."

It's the same as on any other forum, use the ^ symbol (upper csase 6), i.e., tan^-1.
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Old November 14, 2002, 10:32 AM   #10
yzguy
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ok, cool... just wondering thanks
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Old November 14, 2002, 12:58 PM   #11
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Mal H,

Thanks, I am familiar with the use of the caret (^) but did not use it as it is not used on any of the calculator keyboards I have ever seen and I sought to describe the label of the arctan key. What I would like to have, and should have said, is the superscript. Can you help?
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Old November 18, 2002, 06:01 PM   #12
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Huck, sorry for the delay, just got back from a biztrip.

Most superscripts are available using non-standard fonts, but they may come out looking like wingdings on someone elses screen. The only standard ASCII superscript is the square, e.g., sin²ß cos²ß = ¼ sin² 2ß

You get the ² , and other special characters, by holding down the ALT key and entering 253 (for ASCII char 253) on your numeric keypad (can't use the upper row of number keys).
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