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MOA Means What
Posted: Sun Apr 25, 2010 10:00 am
by Mr. Nail
Im just getting into tactical adjustment knobs and wanna know what MOA means.
Re: MOA Means What
Posted: Sun Apr 25, 2010 11:05 am
by bearandoldman
Mr. Nail wrote:Im just getting into tactical adjustment knobs and wanna know what MOA means.
Approximately one inch at 100 yards.
Posted: Sun Apr 25, 2010 11:18 am
by perazzi
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)
Or, as Bear said, 1 inch at 100 yards, and 1/2" at 50..
Posted: Sun Apr 25, 2010 11:50 am
by Mr. Nail
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.
Posted: Sun Apr 25, 2010 12:18 pm
by bearandoldman
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/
Posted: Thu Jun 23, 2011 4:48 pm
by Jack D
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????
Posted: Thu Jun 23, 2011 4:59 pm
by bearandoldman
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????
Posted: Thu Jun 23, 2011 6:37 pm
by Jack D
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?
Posted: Thu Jun 23, 2011 7:35 pm
by bearandoldman
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
Posted: Thu Jun 23, 2011 11:40 pm
by Bullseye
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.
R,
Bullseye
Almost a headache
Posted: Fri Jun 24, 2011 4:00 pm
by Coach1
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.
Posted: Fri Jun 24, 2011 6:21 pm
by Jack D
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?
Posted: Fri Jun 24, 2011 7:28 pm
by Bullseye
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.
R,
Bullseye
Posted: Fri Jun 24, 2011 8:16 pm
by Jack D
Fair enough. If that's the way it's done. That's the way I'll do it, too. Thanks, BUllseye
Posted: Sat Jun 25, 2011 4:18 pm
by blue68f100