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Old January 9, 2019, 05:51 PM   #26
44 AMP
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hmmm, let's see...

take a rifle bullet at 3,000fps...
and, to make it easy lets say 1 in 12" twist..
so that's 1 turn per foot, and 3,000 feet per second x 60 seconds in a minute..

I get 180,000 rpm, rotational speed

Somebody else can tell us how that compares with a power drill, or the compressor vanes in a turbocharger..or jet engine...

Sounds really fast, to me, but is it?
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Old January 9, 2019, 06:08 PM   #27
zeke
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maybe 30 revolutions at 100 yds? Never was real good at math when younger, and much older now
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Old January 9, 2019, 09:35 PM   #28
HiBC
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It is pretty high rpm,but the answer s right in front of us. Every thing slows down,but one turn in 12 inches ? Is one turn in 12 inches. Or 3 per yard....

Sort of dampers the theory of the spinning bullet buzz sawing the insides of a critter.If nothing slowed down,the bullet would make about 1 1/4 turns passing through a deer.
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Old January 10, 2019, 08:40 AM   #29
Mike Irwin
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To expand on my comments, I'm trying to find the photos that I've seen over the years of bullets in flight showing how the "atmosphere" for lack of a better word, flows around a bullet.

Essentially, a high velocity bullet's nose is in a fairly static bubble as it flies, meaning that it really has very little effect on the bullet's path.

The best photos that I've found are on the Wikipedia page on external ballistics.

This one, in particular, shows both the bow shock wave and the trailing turbulence path from the bullet's base.

https://en.wikipedia.org/wiki/Extern...llet,_1888.jpg


In the images I've seen where bullet bases are imperfect, the trailing turbulence path is a LOT more confused and decidedly not symmetrical.
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Old January 10, 2019, 10:41 AM   #30
briandg
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I was always pretty good at math. By using my skills with physics and other disciplines, I can say with absolute confidence that a bullet that was fired from a rifle with a 1;12 twist, travelling at pretty much any realistic velocity will rotate 100 times at 100 feet, and 300 times at 300 feet.

The information shared here has been great.

To address the buzz saw effect, almost anyone here has seen gel tests. Myself, I've never seen any one of them with a buzz saw, whenever I have seen evidence of rotation, it's been one rotation in the block, just as it would be in flight.

But we are talking about accuracy, and just offhand, I think that mike has provided the best information as well as links to pages that can confirm it and provide further information.
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Old January 10, 2019, 11:07 AM   #31
Don Fischer
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Something to think about. Year's ago Speer brought out the mag tip bullet. The idea was that the tip of a bullet melts off soon in flight. They had a high speed photo of it happening to sell their idea. If that is true then banged up bullet's don't hurt a thing. I think we can go even farther back than the mag tip and see the Rem core lock.Not much exposed tip on it either and it's a great bullet. On the other hand seem's I read somewhere that the plastic tip protect's the tip of the bullet. Probably does but better at starting opening I would think. Not sure the tip below the jacket need's protecting.
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Old January 10, 2019, 11:16 AM   #32
zeke
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Guys-Thanks My math skills are not good. Also excellent link.
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Old January 10, 2019, 11:32 AM   #33
T. O'Heir
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The only part of the bullet that matters is the base. If the base is damaged, in any way, the gases go in odd directions. That throws accuracy off.
Makes no difference what the point looks like. Think in terms or the plethora of point shapes. All of 'em are accurate.
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Old January 22, 2019, 02:31 PM   #34
Gas Bag
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IMHO, no it doesn't. The deformity is too small to mean much.
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