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Old October 4, 2012, 06:02 PM   #24
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Join Date: April 18, 2011
Posts: 518
Originally Posted by zombietactics:
You're missing the point. It's not a matter of diameter being important (or not) in terms of calculating cross-sectional area, it's a matter of diameter being insignificant to the larger problem within the range of possible values.
Well, that is not what you said earlier.

And no one here has said that it is the only value of importance either.

Originally Posted by zombietactics:
If you want to get into metrology and physics, the very first thing of importance is to make sure you have adequately described the problem in terms of known physical principles, and secondly to be certain you are measuring the right thing. Everytime I see someone use diameter in some supposed calculation of internal, external or terminal ballistics ... well, I know it's going to be a gun guy, not a physicist or metrologist.
Then you haven't seen Bullet Penetration by Duncan MacPherson (an aerospace engineer) or Quantitative Ammunition Selection by Charles Schwartz. Both models offered in their respective books use diameter/cross-sectional area as one of many important factors and both models do a fantastic job (highly correlated and highly accurate) of predicting penetration and mass of the permanent wound cavity.

Originally Posted by zombietactics:
I'm not going to stoop to the level of insult based upon some reference to a grade level.
I didn't insult you. I simply stated that fourth graders are taught this very equation and that as such, it is common knowledge. You can dispute the equation all that you wish, but it still stands that A = пr²
My favorite "gun" book -


Last edited by 481; October 4, 2012 at 06:14 PM.
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