Bullet RPM Upon Leaving the Barrel

OK. There are some advantages in working in a building full of engineers and their uber-powerful computers. Not many, but some. ;)


One has proven to be the ability to confirm or dispel some engineering related myths. The one most recently in my sphere of annoyance is having read that "the bullet" leaving the muzzle of a poodle shooter is rotating in excess of 150,000 RPM.


That just didn't sound right to me! But I was able to confirm that in some cases not only was it true but that in some other cases that number proved really really low. Yeah, I said: [size=2em]LOW[/size]. :o


Below I will "show my work" and you can cypher it for yourself. But here is the bottom line:


1:7 twist. 3000 FPS. RPM in excess of 308,000. HOLY CRAP BATMAN!! http://www.pic4ever.com/images/229.gif


This formula, this number, this mathematical result has now been verified by three humans (2 of which do not like each other even a little bit), the computer application "Math-CAD", "MatLab", . . . and another app I can't remember the name of, but anyway all three of them run on what us mear mortals would rightly think of as "super computers". This is not a mistake! :o




Here is the formula. Verify it for yourself:


http://www.esrdc.com/art/rpmformulascan.jpg