# ??? conversation for fun

#### mark fox

##### Well-Known Member
Any one know what bc=i* (w/d)^2 what is the meaning????

what about? bc=? ( dms/wds/wpsa) bp

#### tinkerer

##### Well-Known Member
bc=i* (w/d)^2

Ballistic coefficient= Mass Moment of Inertia X (width divided by diameter) squared.

That's it physically and mathematically. I do not know if its accurate without researching though.

Here;s a link to actual math.

http://en.wikipedia.org/wiki/Ballistic_coefficient

Larry
tinkerer

#### mark fox

##### Well-Known Member
bc=? (dms/wds/wpsa)

explained b.c. dont mean SH** - when driven slowly - with a profile that sucks A** some calibers i.e. 338 lapua seem to defi the laws of gravity. there is somthing to be said about a 300 grain .800 bc bullet seems to just stay the corse past transonic. mass resists change.... The sad part is just think if it went 3400 fps. Time of flight and the side profile that sucks a** is its only short fall. it dont like full value wind. but you cant have your cake and eat tooooooo.... ( unless you shoot 7mm 190 grain bullet at 3400 fps)

markfox

#### lynxpilot

##### Well-Known Member
I think the w is actually small omega, which would correlate to speed of rotation in time to the minus one power. After all, width and diameter are the same thing.