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# Maths question for someone with brains ?

#8
03-20-2008, 11:51 PM
 Platinum Member Join Date: Feb 2005 Location: USA Posts: 2,598
Take 1.0472 inches which is 1 MOA at 100 yards and divde it by 100 and then multiply the answer by the yards in 100 meters and then multiply by 20 and that is your answer..
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#9
03-20-2008, 11:56 PM
 Gold Member Join Date: May 2007 Location: VICTORIA AUSTRALIA Posts: 912
Thanks fellas !

I knew I'd get a bite if I cast that one out there !

Many thanks again !

DUH
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With each step in the bush, you are a step closer.
#10
03-21-2008, 12:16 AM
 Platinum Member Join Date: Feb 2005 Location: Nevada Posts: 2,782
1 MOA = 0.01'00" = 0.0166667° ----- 100M(Tan(0.0166667°)) = 0.0290888M @100M.
So, 1 MOA = 29.088822 mm. 1 inch = 25.4 mm
Therefore 1 MOA = 1.145229" @ 100 METERS
20 MOA's equals 22.90 inches.

This way is more complicated but Willy's46 gave me no choice. He'd already done it the way I would have. Lot of fun!
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Last edited by Eaglet; 03-21-2008 at 12:22 AM.
#11
03-21-2008, 01:08 AM
 Gold Member Join Date: May 2007 Location: VICTORIA AUSTRALIA Posts: 912
O.K.

This will test you all,

If I dialled 20 moa, and infact shifted the group 25 " in elevation, how many moa will I be out if I ran these numbers at 700 M

338 edge
300 smk
velocity 2830

alt 200 ft
temp 80 degrees
rh 46 %
bp 30.0

Just have a feeling that incorrect click adjustments may be throwing my elevation out ?

Hope the question gives you everything you need to answer it.

Thanks guys

DUH
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With each step in the bush, you are a step closer.
#12
03-21-2008, 02:10 AM
 Platinum Member Join Date: Dec 2001 Location: Mukilteo, WA Posts: 1,092
You need to nail down the click value on your scope, while eliminating other variables (is it securely mounted now? Are you sure it's holding zero?) or you may be chasing your tail for a long time.

Try a yardstick test at 100. Put the stick vertically on the target. With the rifle very securely held, put your crosshairs on the very top of it and have somebody else crank the turret while you watch the reticle. Ensure it moves smoothly and that each click seems to move the same amount without getting hung up or jumping at all. See how many clicks it takes to get to the bottom of the stick. Do it a few times until you're sure of the answer.

That will tell you what your scope is doing without including possible errors created by shooter, rifle or mounts.
#13
03-21-2008, 03:38 AM
 Gold Member Join Date: May 2007 Location: VICTORIA AUSTRALIA Posts: 912
Jon,

There is no problem now with the mounts. All rock solid.

Basically if the previous posts are accurate, for 20 moa dialed on my scope I should get 22.9" up instead of the 25 I accually get " ? That itself will cause grief.

The rifle simply tack holes groups like I have never seen, but I struggle for good first round elevation dope.

I gave the 700 M example because I routinely practice on a steel gong at that range, and I would like to know what elevation moa others get when they run the previous mentioned numbers through their PDA. I can then compare that to my adjusted drop chart. If they match I feel I have found the missing piece of the puzzle.

So basically I'd like to work out the moa diffence at 700m with the 2 " difference from the 20 moa dialed ? Did that make eany sense ? I think from memory you should get around 16.75 up. Would the difference in click adjustments result in a corrected dope of between 13-14 moa for the 700 M distance

DUH
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With each step in the bush, you are a step closer.
#14
03-21-2008, 10:07 AM
 Platinum Member Join Date: Mar 2007 Location: MN Posts: 1,219
If your scope has shifted 25" when you say it should have shifted 22.9" (corrected for MOA to to inches per 100M) that means that your scope is moving 100.9% of what you want it to. Are all of your adjustments moving the bullet 1.09 times what they should be? If so, that means that your scope is not tracking what it is advertised for.
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