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Formula for calculating amount of moa in inclined rail ?
Posted: Thu Mar 08, 2018 7:45 am
by breacher
Is there a formula ?
I have a flat rail. I want to machine the base to obtain a particular amount of moa incline.
I could just do trial and error in tiny increments but if there is a formula to use that would be handy.
Re: Formula for calculating amount of moa in inclined rail ?
Posted: Thu Mar 08, 2018 7:52 am
by meles meles
Maybe you should be asking Pythagoras or Euclid...
Sometimes we aren't sure you oomans is the cleverest species on the planet.
Re: Formula for calculating amount of moa in inclined rail ?
Posted: Thu Mar 08, 2018 7:55 am
by ovenpaa
Moa is about 1" at 95.5 yards, 1" at 3438 inches, so 1 Moa = 1/3438" for rings an inch apart, 2/3438" for 2 inches apart. So rings 3.438" apart, 10 Moa shim, 10Moa * 3.438"/3438 = 0.01" variance betweeen ends.
Alternatively, I use a spreadsheet that does the calculation for me and gives me the variance in millimetres required along a given distance when I manually machine rails.
Re: Formula for calculating amount of moa in inclined rail ?
Posted: Thu Mar 08, 2018 9:18 am
by Kungfugerbil
Another way is, for example for a 20MOa incline on a 6 inch rail:
20 MOA is 1/3 degree. For 1/3 degree incline at 6" it is (1/3) X (pi/180) X 6 = .034907" = .035"
Build-up = angle X pi / 180 X bar length
Re: Formula for calculating amount of moa in inclined rail ?
Posted: Thu Mar 08, 2018 9:38 am
by breacher
Ok tbanks guys.
Re: Formula for calculating amount of moa in inclined rail ?
Posted: Fri Mar 09, 2018 10:22 pm
by Hrun
meles meles wrote:Maybe you should be asking Pythagoras or Euclid...
Sometimes we aren't sure you oomans is the cleverest species on the planet.
Give us some credit.. someone managed to do the math in order to sell us a 20 moa rail.