# Calculating Drift.

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Topshot, Jul 30, 2009.

1. ### TopshotWell-Known Member

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For very long shots, is it possible to convert the horizontal drift components of the Coriolis Effect and Spin drift into one single wind drift component that can be added to or subtracted from the measured field wind value?

If so this would be a quick and simple way to include these components without the long drawn out process of calculating these as separate values for a particular shot.

Example. Say you are shooting at 1200 yards with a 338 edge and 300 grain SMK @ 2800 fps with a right hand twist 1;10 barrel, with a light wind measured at 3 mph from 3 or 9 o'clock. Could you add or subtract, say a 1 or 2 mph wind value to compensate for the Coriolis effect and Spin Drift. Or is this a too simplistic way of doing things?

In my area I have worked out that the Coriolis Effect is equal to about a 0.4 mph right to left wind and my spin drift value is about equal to a 1.5 mph wind to the right at 1000 yards.

Last edited: Jul 30, 2009
2. ### AJ PeacockWell-Known Member

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Last edited: Jul 30, 2009

3. ### kiwi3006Well-Known Member

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The easiest way to do it is to buy Loadbase 3.0 and it will do it all for you.

Stu.

4. ### TopshotWell-Known Member

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Thanks fellas,

Just finished reading Bryan Litz book and that is what got me thinking.

I fully understand Coriolis and spin drift and have the programs to calculate it.
These two components are not linea and seem to behave similar to wind drift when taken individually.

What I am trying to do is come up with a simple field method that can link these components to wind drift. Then all I would need to do is apply a correction factor to all my wind readings.
Do you think this possible?

5. ### kiwi3006Well-Known Member

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Yes it is possible, simply make up a look up table, although it would be a pretty "busy" one as you would need to do it for several angles of fire and then remember wether it was a positive or negative effect.

6. ### jmasonWell-Known Member

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Kiwi is right. It will be even worse for multiple latitudes. I don't know what your using for software but LB3 makes it easy on you. All those factors are on one screen and you can chose to use them or ignore them. Much easier that filtering data from a spread sheet.

7. ### MikecrWell-Known Member

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How are you using LoadBase in the field?

8. ### jmasonWell-Known Member

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Pocket PC (PPC)

9. ### MikecrWell-Known Member

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I'm amazed an access database would even work on windows mobil. PseudoExcell doesn't...
I'll have to try it sometime

Last edited: Aug 1, 2009