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M.O.A. Primer from National Shooting Sports Foundation

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CT_Shooter
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M.O.A. Primer from National Shooting Sports Foundation

Post by CT_Shooter » Mon Nov 06, 2017 4:16 pm

I bookmarked this page a few years ago, but today when I went to read it again, it was gone. Nonetheless, I found an archived copy on http://www.archive.org's Wayback Machine, which is really cool. Actually, the entire site is pretty extraordinary for what it contains. It's also an example of how internet based digital information lives on and on.

Anyway, it seems like a useful and simple primer for using MOA in the field, and I want to share it.
https://web.archive.org/web/20130815214548/http://nssf.org/video/facts/MOA.cfm wrote:
Minute of Angle (MOA)

QUICK FACTS

-A Minute of Angle (MOA) is an angular measurement.

-A MOA is 1/60th of a degree.

-1 MOA spreads about 1" per 100 yards. (actually 1.047")

-1 MOA is a different size at different distances, 8" at 800 yards is still just 1 MOA.

100 yds 200 yds 300 yds 400 yds 500 yds 600 yds 700 yds 800 yds
1" 2" 3" 4" 5" 6" 7" 8"

RYAN'S TIPS FOR USING MOA

1. Always think in increments of 1 MOA at whatever distance you are shooting.

For example, imagine you are shooting at 300 yards. You know that a MOA spreads out 1" per 100 yards, so 1 MOA at 300 yards is 3". Therefore, for your calculations at that 300 yard target, you should think in 3" increments. By doing so, you can easily see that 2 MOA is just 2 of those 3" increments, or 6" total. And likewise, 1/2 MOA is 1/2 of those 3" increments, or 1.5".

If you are having trouble determining the increments in your head and would rather have a formula, you can try this method. Divide the distance (in yards) you are shooting by 100 and you will know how big 1 MOA is in inches. For example, imagine you are now shooting at 250 yards. 250 / 100 = 2.5. So, 1 MOA at 250 yards is 2.5".

2. Determine how many 1 MOA increments will fit into the adjustment you are trying to make.

For example, imagine you are trying to adjust 8" at 400 yards. You already know to think in 4" increments for this example. Two 4" increments (or 4" chunks) fit into the 8" of needed adjustment so you would need to adjust 2 MOA.

If you are having trouble doing this in your head and would rather have a formula, you can try this method. Divide the number of inches you want to adjust by number of inches in 1 MOA at that distance. For example, imagine you are now shooting at 600 yards and want to move the impact of the bullet 18". You know that 1 MOA at 600 yards is 6" from the previous step. 18 / 6 = 3. So, a 3 MOA adjustment at 600 yards will move the bullet 18".

3. Think in MOA and not in "clicks" on your scope.

Although the majority of retail scopes adjust in 1/4 MOA per click adjustments, some scopes adjust in 1/8, 1/2 or even 1 MOA per click. Once you know how many MOA to adjust, you can then make the adjustments on your particular scope. For example, if your scope adjusts in 1/4 MOA per click, and you want to adjust up 2 MOA, you need to realize that 4 clicks adjust 1 MOA so you need 8 clicks total.

FORMULAS

-(Distance to target in yards) / (100) = inches per MOA at that distance

-(Number of inches of adjustment needed) / (inches per MOA at that distance) = MOA adjustment

-(Number of clicks per 1 MOA on scope) x (MOA adjustment) = adjustment in clicks on scope

Note, if you insist on using 1.047" per 100 yards instead of 1" per 100 yards, you must multiply the (inches per MOA at that distance) by 1.047.

EXAMPLES


If 1 MOA is 1" at 100 yards, how many MOA is 2" at 200 yards?

It is still just 1 MOA. Remember, a MOA is an angular measurement that gets bigger with distance. 1" at 100 yards and 12" at 1200 yards are both 1 MOA.

If your bullets are impacting 16" to the left at 800 yards, and ignoring any wind effect for now, how many MOA do you need to adjust and in which direction?

2 MOA to the right. Remember, the first step is to think in 1 MOA increments at whatever distance you are shooting. Since 1 MOA at 800 yards is 8", you should think in 8" increments for this problem. The next step is to think about how many increments of 1 MOA fit into the distance you want to adjust. Two 8" increments fit into the 16" we want to adjust, so we are going to adjust 2 MOA. Since the bullets are impacting to the left, we want to adjust them to the right.

At 50 yards, how far will a 10 MOA adjustment move the impact of the bullet in inches?

5 inches. If 1 MOA at 100 yards is 1", then at half the distance, 1 MOA is half as big and is 1/2". Likewise, 1 MOA at 25 yards is 1/4". So, if you think in 1/2" increments, and add up 10 of those 1/2" increments, you come up with 5 inches.

If you scope adjusts in 1/4 MOA (it may say 1/4" per 100 yards on scope), how many clicks are needed on the scope to adjust 10" at 200 yards?

20 clicks. 1 MOA increment at 200 yards is 2". 5 of those 2" increments fit into the 10" of adjustment needed, so a 5 MOA adjustment is needed. 4 clicks on the scope equal 1 MOA. So, if every 4 clicks equals 1 MOA, you will need 5 of those 4 click adjustments, or 20 clicks total.
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Re: M.O.A. Primer from National Shooting Sports Foundation

Post by sledman » Sun Nov 19, 2017 5:06 pm

Nice find! Thank you for posting this, Sir.
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Re: M.O.A. Primer from National Shooting Sports Foundation

Post by CT_Shooter » Sun Nov 19, 2017 5:26 pm

sledman wrote:Nice find! Thank you for posting this, Sir.
You're welcome. And as a first time poster here, you're also welcome to this forum from CT. I hope to read more from you.
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Re: M.O.A. Primer from National Shooting Sports Foundation

Post by sledman » Sun Nov 19, 2017 5:32 pm

Thank you for the hospitality. I've recently retired, so I hope to visit the forum a little more frequently.
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Re: M.O.A. Primer from National Shooting Sports Foundation

Post by The Wiz » Sun Nov 19, 2017 7:50 pm

I'm so confused... :?
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