Spinning Bullet on Ice for Real

[kobsw]

I have to admit I didn't think it was real.

Original (FYI: Do a search for spinning bullet on ice and there are many other examples)

YouTube - ‪Spinning .40 cal bullet on ice‬‏

Proven to be real by Mythbusters (Spinning Bullet occurs at 9:19 and a few other times after that)

YouTube - ‪MythBusters S09E07 Spy Car 2 HD(part3/3)‬‏

I know it's way off topic of most of our interests around here but some might find the physics of the whole thing thought provoking. See how the various FMJ rounds being used don't deform and have enough energy to spin for several seconds.

***THIS is VERY DANGEROUS and SHOULD NEVER BE ATTEMPTED***

Everybody have a good week.

Regards,

Kobsw

 

[jkc]

I thought this was informative, and illustrative, of the phenomena that a bullet is affected in two ways by being pushed by propellant gasses down the barrel of a gun ...

It is given two vectors --- forward, and , rotational. The forward vector pushes the projectile down the barrel, the rifling (or whatever passes for it) imparts "spin" to the projectile, imparting gyroscopic stability to the projectile's in-flight trajectory...

That the forward movement of the bullet is impeded and captured by ice, and that the bullet keeps spinning, illustrating the loss of one, and the retention of the other vector, seems to me to be "way cool", and I intend to replicate this experiment, in the unlikely event an opportunity presents itself, locally, soon.

 

[David LaPell]

I thought it suspicious too until it was proven, but after reading how much algebra is involved in ballistics and all that, it can be mind boggling what might be possible. I thought about trying it, but to what purpose.

 

[OKFC05]

When I first saw it, a quick check of the equations showed it was entirely possible, provided the bullet experienced an inelastic collision with the ice, losing all its forward momentum without significantly affecting its angular momentum.
Depending on barrel twist and MV, a pistol bullet typically spins at 60,000 to 80,00 rpm.

However, if the bullet managed to have an elastic collision with something in the ice, it could easily bounce back with enough speed to penetrate your hide.

Once again, I'll watch from WAY over here.....