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Old 09-27-2017, 05:20 PM   #61
Anthony
 
Join Date: Feb 2005
Location: Berkeley, CA
Default Re: GURPS ULTRATECH ballistics?

Quote:
Originally Posted by mlangsdorf View Post
I stole this from Doug's spreadsheet:
volume in cubic cm = (PI*(Bore/2)^3 + PI/12*Bore^2*(2*Bore*Aspect Ratio-Bore)) / 1000
For a bullet with a perfect half-sphere rounded tip:
Volume of tip = 2/3 * pi * r^3
Volume of cylinder = pi * r^2 * (length - r), or pi * r^3 * (aspect ratio*2 - 1)
where bore is bullet bore in milliimeters and aspect ratio is bullet length / bullet bore.

Accumulating variables, we get pi * r^3 * (AR*2 - 1/3), or pi*B^3*(AR/4 - 1/24).
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