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#36 – Gyroscopic Drift

Gyroscopic Drift

00:38:57  | Gyroscopic drift, also known as Spin Drift; this episode is from Chapter 6 of Applied Ballistics for Long Range Shooting. Bryan and Mitch discuss the nature and physical mechanism of this mysterious variable, as well as how the formula for calculating spindrift was developed and verified thru live-fire testing.

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  • Jayden Bjarnesen says:

    Hey bit of an odd one and maybe just a slight misunderstanding of the effect on my part, if there is an introduction of orographic lift from a vertical wind or a heavy head wind, would there be an increased wind experienced under the chin of the projectile? If so would this increase the effects of spin drift?

    Thanks in advance!

    • Bryan Litz says:


      Good question.

      Orthographic lift tends to be a very transient condition for a bullet to fly thru, as in when it goes over the edge of a cliff/ridge, etc. Contrast this with the pervasive effect of the arcing trajectory; the pervasive influences (gravity, arcing trajectory) will drive most of the effect. The transient conditions (orthographic lift) do matter, but not often not enough to notice since they only apply over a short range.

      Yes, an orthographic wind coming up from under a bullet will increase spin drift over the range it applies, but over most earthly terrains, the effect is too minimal to discern from the pervasive effect of gravity on the trajectory.

      Take care,

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