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Current Posts => Latest Spin => Topic started by: Mark Magyar on May 20, 2011, 03:39:53 PM

Title: Bullet spins like top on ice...
Post by: Mark Magyar on May 20, 2011, 03:39:53 PM
I don't happen to watch tv a whole lot but I was surfing the channels and Myth Busters happened to be on. They were testing this video to see if it could be confirmed or not.
http://www.youtube.com/watch?v=b1btKoF_HZk&feature=mfu_in_order&list=UL (http://www.youtube.com/watch?v=b1btKoF_HZk&feature=mfu_in_order&list=UL)
Myth Confirmed.

Reminds me of the Chinese Whip Top video I've seen as the bullet is shaped similar to that of a whip top.
Title: Re: Bullet spins like top on ice...
Post by: Pulp on May 20, 2011, 05:01:56 PM
What was the starting way of spinning?
Title: Re: Bullet spins like top on ice...
Post by: ta0 on May 20, 2011, 06:32:05 PM
I don't watch too much TV either, but I caught the preview and I HAD to watch it.  The TV guys could not at first reproduce it with slabs of ice in the summer but when they tried again in the winter during a snow storm it worked. It is pretty amazing that the bullet is stopped without being deformed. I guess the ice must become water (or vapor) instantaneously when the bullet hits.

Quote
What was the starting way of spinning?
The barrels of guns have grooves to impart spin to the bullets.  From Wikipedia: "Rifling is the process of making helical grooves in the barrel  of a gun or firearm, which imparts a spin to a projectile  around its long axis. This spin serves to gyroscopically  stabilize the projectile, improving its aerodynamic  stability and accuracy." Spinning rates can be over 300,000 RPMs!!!!  :o

Who would have thought that a gun could spin a top?  ;)

(http://ta0.com/museum/images/patents/USPat-202742_Royal-Pistol_small.jpg)
Title: Re: Bullet spins like top on ice...
Post by: Pulp on May 21, 2011, 02:15:29 AM
My question was if the bullet was putting in movement by a normal use of the gun, shooting directly to the ice...
Title: Re: Bullet spins like top on ice...
Post by: ta0 on May 21, 2011, 09:38:50 AM
(http://My question was if the bullet was putting in movement by a normal use of the gun, shooting directly to the ice...)Yes, somehow the ice stopped the bullet without deforming it and the bullet just kept spinning because of the spin given by the barrel. On the TV show the bullet ended up spinning while laying on the side but on the youtube videos they got some nice spins on the tip, just like a top.
Title: Re: Bullet spins like top on ice...
Post by: Jack on January 06, 2015, 12:37:54 AM
another case posted just days ago!

https://www.youtube.com/watch?v=mlonJKoRWsA
https://www.youtube.com/watch?v=YML0DN_cugI
Title: Re: Bullet spins like top on ice...
Post by: the Earl of Whirl on January 06, 2015, 04:42:02 AM
Hmmm.  I don't remember this discussion from before.  We have some people in the congregation who do a lot with guns/rifles.  They will be interested in this.

The two videos that Jack posted don't spin as long as that first one but the last one shows a bullet spinning nearly on its side and somehow correcting itself so that it spins upright!
Title: Re: Bullet spins like top on ice...
Post by: kevinm on January 06, 2015, 07:30:19 PM
^ That sure enough sounds like an Ohio thing. Mike, if you are going to film
it for youtube, remember to shout, "Hey y'all watch this!" before you start shooting.
Title: Re: Bullet spins like top on ice...
Post by: Austen on January 06, 2015, 10:04:54 PM
We can try this out!!! We got plenty of bulletts but the Earl of whirl will have to bring the ice!!!
Title: Re: Bullet spins like top on ice...
Post by: the Earl of Whirl on January 09, 2015, 12:44:18 PM
Just what I thought.  I showed them this video and they all got excited and started talking about how they could do it.  They just have to remember to first say "Hey y'all, watch this!"
Title: Re: Bullet spins like top on ice...
Post by: Dick Stohr on January 09, 2015, 02:23:44 PM
I would like to know why the bullet does not go through the ice? Am I missing something? How thick/thin does the ice need to be? What size bullet and how much powder? Inquiring minds want to know!
Title: Re: Bullet spins like top on ice...
Post by: ta0 on January 09, 2015, 03:10:20 PM
I would like to know why the bullet does not go through the ice? Am I missing something? How thick/thin does the ice need to be? What size bullet and how much powder? Inquiring minds want to know!

My guess is that the kinetic energy of the bullet goes into the phase change from ice to water (or vapor). It is in fact a very interesting phenomenon and I would like to see some explanation or study about it.

I once read on a physics book that bullets travel a short distance in a liquid (e.g. water), no mater what their initial velocity is, because the faster they go the faster they need to move the material out of the way. On the other hand, making the bullet longer will make it go further, if I recall correctly.
Title: Re: Bullet spins like top on ice...
Post by: lincolnrick on January 09, 2015, 09:54:33 PM
I would like to know why the bullet does not go through the ice? Am I missing something? How thick/thin does the ice need to be? What size bullet and how much powder? Inquiring minds want to know!

My guess is that the kinetic energy of the bullet goes into the phase change from ice to water (or vapor). It is in fact a very interesting phenomenon and I would like to see some explanation or study about it.

I once read on a physics book that bullets travel a short distance in a liquid (e.g. water), no mater what their initial velocity is, because the faster they go the faster they need to move the material out of the way. On the other hand, making the bullet longer will make it go further, if I recall correctly.

Mythbusters did a segment on bullets and water.  They shot various caliber pistols/rifles into a large pool and found that indeed, all projectiles loose most of their speed once they start traveling through water. From their webpage:

'All supersonic bullets (up to .50-caliber) disintegrated in less than 3 feet (90 cm) of water, but slower velocity bullets, like pistol rounds, need up to 8 feet (2.4 metres) of water to slow to non-lethal speeds. Shotgun slugs require even more depth (the exact depth couldn’t be determined because their one test broke the rig). However, as most water-bound shots are fired from an angle, less actual depth is needed to create the necessary separation.'
Title: Re: Bullet spins like top on ice...
Post by: Dick Stohr on January 10, 2015, 10:32:44 PM
It makes sense that a bullet slows quickly in water but ice is a solid. Why does the bullet not penetrate in ice like it does in wood? I would think the ice would crack. How thick does the ice have to be to not crack? If you shoot bullets at concrete the bullet deforms and flattens, why not with ice?
Shootest????????????????????????????????
Title: Re: Bullet spins like top on ice...
Post by: ta0 on January 11, 2015, 12:05:30 AM
It makes sense that a bullet slows quickly in water but ice is a solid. Why does the bullet not penetrate in ice like it does in wood? I would think the ice would crack. How thick does the ice have to be to not crack? If you shoot bullets at concrete the bullet deforms and flattens, why not with ice?
Shootest????????????????????????????????
In the first and third videos they seem to be shooting at snow and if it skips the surface some distance it is plausible that the bullet would slow down without deformation. On the second one the impact (at an angle) seems to be on real ice, but perhaps somewhat borderline. It does make a big crater what would explain the dissipation of the energy. What really surprises me is that in that case the bullet is not deformed.

A google search found this unclassified research by the US Army on projectile and fragment penetration in snow and frozen soil: link (http://www.dtic.mil/dtic/tr/fulltext/u2/a025972.pdf). Figure 13 shows penetration for different compact densities of snow and three calibers. In the conclusions section it says that aluminum FSP (flat soft point?) projectiles started to deform in snow at impact velocities greater than 900m/s.

Water is a very unusual material that behaves in strange ways. The results may depend drastically on the specific type of ice/snow that is impacted.
Title: Re: Bullet spins like top on ice...
Post by: Shootist on January 11, 2015, 10:15:34 PM
It makes sense that a bullet slows quickly in water but ice is a solid. Why does the bullet not penetrate in ice like it does in wood? I would think the ice would crack. How thick does the ice have to be to not crack? If you shoot bullets at concrete the bullet deforms and flattens, why not with ice?
Shootest????????????????????????????????

Dick,  Disclaimer: I live in Alabama and the only ice I see is in my glass of sweet tea. ???? While I have trained & shot many weapons during the course of my career, I have never shot into ice.

I have watched the videos on YouTube involving the spinning bullets on ice. The bullets in the video are a "Full Metal Jacket Bullet". A round nose smooth hard copper encased lead core bullet. This bullet will not deform as easy as a "Jacketed Hollow Point Bullet" made for self defense.

I think Ta0 is correct when he states that the bullet is skipping off the ice. Here's my opinion why.

Coefficient or Friction also know as Drag Factor: A bullet shot at a concrete wall will most likely deform due to the drag factor of the concrete wall material being more course than ice. A Full Metal Jacket Bullet with it's smooth round nose and the ice being a smooth and slick surface has a lower drag factor. This lower drag factor would cause the bullet to skip on the ice. There is not enough friction on the ice to grab the bullet long enough to cause it to deform on impact.

Subsonic Ammunition is another way to help prevent over penetration into the ice.
Title: Re: Bullet spins like top on ice...
Post by: the Earl of Whirl on January 11, 2015, 10:57:49 PM
Isn't there more ice up in Canada, Jack?  Either that or Shootist could make a visit to a local ice rink >:D
Title: Re: Bullet spins like top on ice...
Post by: the Earl of Whirl on February 07, 2015, 10:26:58 AM
Ha ha!  "Outrageous Acts of Science" is a TV show on the Science channel.  I happened to turn it on and watched it for a bit.  They did a countdown of the top 20.  Guess what was number 11?  Bullets spinning on ice!!!  The guy didn't just shoot one bullet in the ice and go look for it.  He shot a bunch and then went looking. 
Title: Re: Bullet spins like top on ice...
Post by: Jack on February 07, 2015, 07:07:01 PM
Isn't there more ice up in Canada, Jack?  Either that or Shootist could make a visit to a local ice rink >:D

oh i just noticed this, u bet theres pleanty of ice, one might be well advised not to shoot the hockey rink here unless a lynching is what your after  ;)

Ha ha!  "Outrageous Acts of Science" is a TV show on the Science channel.  I happened to turn it on and watched it for a bit.  They did a countdown of the top 20.  Guess what was number 11?  Bullets spinning on ice!!!  The guy didn't just shoot one bullet in the ice and go look for it.  He shot a bunch and then went looking. 

that does it im going out to accost one of the local gangbangers and pester him till he gives me his pea-shooter, be back soon with results of tests @-@
Title: Re: Bullet spins like top on ice...
Post by: ta0 on February 08, 2015, 10:42:57 AM
I could not find that video but there are many other cool videos on the Outrageous Acts of Science website.

Shootist and family: when are you starting a top using bullets? >:D



Title: Re: Bullet spins like top on ice...
Post by: ta0 on February 08, 2015, 02:08:47 PM
Shootist and family: when are you starting a top using bullets? >:D

I looked a little more into this.
I found on Wikipedia that a 0.22 LR bullet (apparently the most commonly sold) has a nozzle velocity of 533 m/s, a mass of 2 gr. and typically spins at 78,750 RPM

One way of spinning a top with a bullet would be to hit it in the perimeter so the momentum of the bullet creates the torque to spin it.
A little bit calculation gives me that in the best case, for the bullet being lodged at the rim of a small top (i.e. a Gladiator), it could make it spin at around 10,000 RPM. So it is theoretically possible, but my guess probably quite difficult, to spin a regular top with a bullet. However, a special target spintop could be designed for this.

Another way to spin a top would be to transfer the rotation of the bullet to the top. I get that the rotational inertia of the bullet is about 100 times less than that of a small top. So, if the bullet was shot down through the crown and became lodged inside the top, to conserve the angular momentum you have to divide its rotation by 100. The Gladiator would spin at less than 800 RPM: not enough but close. A faster spinning bullet could theoretically do it. According to the rifling article on Wikipedia, a bullet from a M16A2 rifle can spin at 314,000 RPM, what would give about 3,000 RPM for the top. In practice, however, you would need to stuff the top with something heavy to stop the bullet, what would increase its inertia, so it may not work after all . . .

Title: Re: Bullet spins like top on ice...
Post by: mailman on February 09, 2015, 02:37:29 PM
I'm not sure there is anything you could stuff a top with that would be able to absorb the energy of a .223 round from an M16 rifle.  Their penetrating power is formidable....
Title: spin top gun real bullet dancing
Post by: Turegano on February 12, 2018, 03:40:13 PM
Note admin: I merged with the above topic, but not sure if that was the subject of this post.
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hello everyone I was surprised to see her dance as a spin top

hola a todos  me sorprendio verla bailar como spin
Title: Re: Bullet spins like top on ice...
Post by: TheSpinForce on February 21, 2018, 10:39:55 AM
This is pretty cool, who would've known
Title: Re: Bullet spins like top on ice...
Post by: Turegano on February 25, 2018, 10:24:32 AM
thank you very much for moving my comment to this I did not know how to do it I wanted to upload the video but nopude and I think someone had already done it but thank you very much it is incredible to see the bullet dancing greetings