MOA Means What

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Mr. Nail
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MOA Means What

Post by Mr. Nail » Sun Apr 25, 2010 10:00 am

Im just getting into tactical adjustment knobs and wanna know what MOA means.

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Re: MOA Means What

Post by bearandoldman » Sun Apr 25, 2010 11:05 am

Mr. Nail wrote:Im just getting into tactical adjustment knobs and wanna know what MOA means.
Approximately one inch at 100 yards.
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Post by perazzi » Sun Apr 25, 2010 11:18 am

MOA- Minute of Angle.

A minute of arc, or arcminute or minute of angle (MOA), is a unit of angular measurement, equal to one sixtieth (1/60) of one degree.[1] Since one degree is defined as one three hundred sixtieth (1/360) of a circle, 1 minute of arc is 1/21,600 of the amount of arc in a closed circle. It is used in those fields which require a unit for the expression of small angles, such as astronomy or marksmanship.

The number of square arcminutes in a complete sphere is

4 \pi \left(\frac{10\,800}{\pi}\right)^2 = \frac{466\,560\,000}{\pi},

or approximately 148,510,660.498 square arcminutes.

*(courtesy of Wikepedia) :roll:

Or, as Bear said, 1 inch at 100 yards, and 1/2" at 50..
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Post by Mr. Nail » Sun Apr 25, 2010 11:50 am

Thanks. On the scope I'm wanting, their offering it in .25 or 1 MOA per click I'm gonna go w/ the .25 for finer adjustment.

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Post by bearandoldman » Sun Apr 25, 2010 12:18 pm

Mr. Nail wrote:Thanks. On the scope I'm wanting, their offering it in .25 or 1 MOA per click I'm gonna go w/ the .25 for finer adjustment.
Most scopes are 1/4 minute clicks, most target/varmint scope will be 1/8 minute per click/
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Post by Jack D » Thu Jun 23, 2011 4:48 pm

So a 1 MOA group at 100 yds. is all shots inside a 1" radius or 2" circle??? Or, in other words, a 2" group at 100 yds is a 1 MOA group????
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Post by bearandoldman » Thu Jun 23, 2011 4:59 pm

Jack D wrote:So a 1 MOA group at 100 yds. is all shots inside a 1" radius or 2" circle??? Or, in other words, a 2" group at 100 yds is a 1 MOA NO 1 MOA is one inch circle at 100 yards.group????
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Post by Jack D » Thu Jun 23, 2011 6:37 pm

Not sure I follow. If each shot is within 1" of the point of aim. Then if the point of aim is in the center of a 2" (1" radius) circle and if all shots fall within that 2" circle, they are all within 1" of the point of aim and the accuracy is within 1 MOA. If a 1" circle at 100 yds is 1 MOA, it seems to me that a rifle (and shooter) that can group 1" @ 100 yds. that has to be accurate to .5 MOA. Am I thinking correctly?

If a rifle is putting all shots in a 2" circle at 100 yards, its accuracy is within 1 MOA. Correct?
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Post by bearandoldman » Thu Jun 23, 2011 7:35 pm

Jack D wrote:Not sure I follow. If each shot is within 1" of the point of aim. Then if the point of aim is in the center of a 2" (1" radius) circle and if all shots fall within that 2" circle, they are all within 1" of the point of aim and the accuracy is within 1 MOA. If a 1" circle at 100 yds is 1 MOA, it seems to me that a rifle (and shooter) that can group 1" @ 100 yds. that has to be accurate to .5 MOA. Am I thinking correctly?

If a rifle is putting all shots in a 2" circle at 100 yards, its accuracy is within 1 MOA. Correct?
no
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Post by Bullseye » Thu Jun 23, 2011 11:40 pm

1 MOA is the measurement of the diameter. Therefore to qualify as a 1 MOA grouping all shots must be inside a 1" dia. circle at 100 yards, or 2" at 200 yards, 3" at 300 yards, etc.

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Almost a headache

Post by Coach1 » Fri Jun 24, 2011 4:00 pm

Well.. a person could get a headache with this. Bullseye's explanation is clear. Thanks.

And knowing what the affect of each click is on your scope is valuable for adjusting for wind affects or simply sighting-in a new rifle / scope combination. Typically, 4 clicks appropriately left or right will move the POI 1 inch toward the POA. Did I get that right? (Vertical is similar)

My shooting partner (S-i-L) has a new Leupold scope for his Stevens .223 bolt action rifle. We plan to sight them tomorrow.
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Post by Jack D » Fri Jun 24, 2011 6:21 pm

Either I'm missing something, or something is missing me. I understand that a 1 MOA group at 100 yds. is all shots in the group inside a 1" circle. But to achieve that no single shot can be more than .5 MOA off of the point of aim (POA) assuming the point POA is in the center of the group. Therefore the rifle has to be firing within .5 MOA accuracy to achieve a 1 MOA group.

Now, I realize it can be slightly more because if a bullet touches a ring, it is counted, but for this argument, I'm assuming center of the projectile. POA is the center of the star. Grey circle is 1".

How am I wrong?

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Post by Bullseye » Fri Jun 24, 2011 7:28 pm

The aiming point is not typically counted in the computation of MOA. Generally you aim for the same spot on the target and then the shot grouping is measured from the difference between the extreme most hits. Since any weapon can have the aim be off, based on who is peering down the sights, the hits are where the grouping spread is measured for the weapon's MOA capability.

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Post by Jack D » Fri Jun 24, 2011 8:16 pm

Fair enough. If that's the way it's done. That's the way I'll do it, too. Thanks, BUllseye
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Post by blue68f100 » Sat Jun 25, 2011 4:18 pm

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