Hi, southpaw:
There's only two ways to calculate BC that I know of. One is to fire a bullet over two chrongraphs a fair distance apart (50 yards plus) and do the math. The other is the Bugless-Coxe method, which you need Hatcher's notebook for. You compare the bullet shape to the table (page 571-572), determine the form factor "i" and divide the sectional density by it. BC = Sd/i. Hatcher's Notebook is still in print and you'll find it very useful.
Sniff around on Brad Millard's site. IIRC, there's another method there. <a href="http://www.cybermesa.com/~jbm/index.html
Later:" target="_blank">http://www.cybermesa.com/~jbm/index.html
Later:</a>
Goto jbm, click on Ballistics, then Calculations, then Bullet Drag & Twist. It's set up for typical high power rifle bullets and won't work with Marshall's bullets because it won't accept a meplat diameter greater than half the bullet diameter. However, you can learn a lot at this site. Note that it gives a different BC for each velocity step. Only Sierra tells you that, and their manual is a good read for intermediate level ballistic theory.
I've got about a dozen "killing power" formulas. None are perfect, but most are useful. For a long discussion, try:
<a href="http://ulfhere.freeyellow.com/ballistics/wounding.html
Bye" target="_blank">http://ulfhere.freeyellow.com/ballistics/wounding.html
Bye</a> for now
Jack
(Edited by Jack Monteith at 9:55 pm on May 16, 2001)