Katana cuts .50 cal. bullets in half - video clip

Originally posted by Chuck.....
I liked the guy carefully cleaning the sword blade off before the test... as if that's gonna make any difference.
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Shame on you Chuck!. Have you never seen a trainer pat a boxer on the back just before the bell rings? This was the same......wishing good luck to someone/something he had put so much time and effort into. :)
 
Well, here are my $0.02:
Number one: the parlour trick with the phonebook executed correctly, is to take it by the spine and rip it appart (which is not much of a trick anymore, as it is actually fairly difficult).

Second: A lead bullet hitting an edge perfectly straight on, doesn't impress me either, but there are always some torque and side forces (not to mention the spinning of the bullet). Suddenly, you have lateral forces on the blade and edge which are small percentage wise but if the total kinetic energy is THIS large, they are still enormous. I am pretty impressed.
 
"We salute those of you who are about to die." ???
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Nothing so pessimistic!

Closer to a sign of affection for something that was a part of him because he had created it.

I might be inclined to do the same if I had just pitted David against Goliath! ;)
 
(not to mention the spinning of the bullet).
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Oh, please, do mention the spinning of the bullet. That's a good thought. It could help explain why the blade appears to chip, but not just chip but have a huge chunk sort of knocked out of it. Anyone have any idea what the rotational velocity of such a bullet might be?
 
Muzzle velocity 2910 feet per second, rifling one twist in 15 inches, comes to 2328 revolutions per second or 139,680 rpm. Of course that's assuming factory ammo or something similar. Even if it's downloaded, though, any rifle bullet has to spin so rapidly that there are going to be substantial side forces no matter how perfectly the edge is aligned to the bullet flight path -- and opposite forces at top and bottom of the bullet, not very far apart.
 
That's counting the entire span of flight. The time and RPM factor play no part. The twist is still (assuming) 1 in 15, and slower as it leaves the barrel. Say you've got a 1-inch wide blade -- it's only going to try and twist 1/15th of 1 rotation as it travels through.
 
Hmm ... circumference of a .50 bullet is 1.57 inches or 0.13 feet. Rotating at 2328 revolutions per second the surface (the copper jacket) is moving at 302 feet per second, and half an inch away it's moving in the opposite direction at the same speed so the combined speed is 604 feet per second. That's slower than a pistol bullet; pistol muzzle velocity starts at about 800 feet per second, but that's all pure side force.
 
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