Posted: 11/21/2006 7:21:22 AM EDT
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I'm doing a project for an aerodynamics class about bullets and have some questions about the ballistic coefficients used by bullet manufactorers. Is the BC constant for a given bullet or does it change with velocity? What I'm interested in doing is figuring out a bullet's BC using data gathered from testing (velocities at different ranges and atmospheric conditions). |
Thanks for the response. |
Sierra is the only bullet manufacturer I know that publishes BC variation with speed. Since BC is basically a measure of a bullet's drag, it should make sense to you that drag will vary as a strong function of dynamic pressure; in this case, the dynamic pressure undergoes an enormous change from its maximum value to its minimum value. |
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This page may be of some help to you... ETA----technical stuff at bottom of page. www.frfrogspad.com/ballisti.htm |
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Slight hijack please forgive me. I was talking to a 1000 meter competition shooter last weekend and he said that he was using flat based projectiles with a lower BC because they did better at "transonic transitions" than boat-tails. I have no doubt that this was true... the guy has enough trophies on his wall to prove he knows his shtuff. My only question was: WTF is a "transonic transition" and why would a flat base do better at it than a boat tail? Any insight or linkage to an explanation would sure be helpful. /hijack |