Overall project length does not "dictate" the rate of spin necessary to stabilize it - it is a complex formula of forward velocity, bullet weight, bullet profile, bearing surface, and variations in density due to various alloys of lead and copper in the bullet geometry, all of which contribute to the rotational energy and inertia at various glide path velocities. Overall length is just a simple number, like gross weight, which can be used by the least sophisticated attempts to correlate some bullet characteristic to rate of spin.
You forgot to include air density. Next time try and at least make it to the SECOND Google result before copying and pasting.
