Papercrafts

[Zenophas]

I've been observing this little devil for years now. He's quite amazing when it comes to making functional guns out of mere paper.

He also makes some really awesome jets and U-boats.

I've always wanted to get into this kind of stuff, but I usually ended up using scrap metal to build skulptures anyway.

[Psychedelic Rhino]

I've been observing this little devil for years now. He's quite amazing when it comes to making functional guns out of mere paper.

That is close to unbelievable!

[S.cavA.rmyG.en]

even if it works its not legal to build fire arms with out the proper lince in the US.

[Psychedelic Rhino]

even if it works its not legal to build fire arms with out the proper lince in the US.

Firing a round with a paper barrel would not be pretty.

[S.cavA.rmyG.en]

even if it works its not legal to build fire arms with out the proper lince in the US.

Firing a round with a paper barrel would not be pretty.

I have seen a cannon made out of duck tape so it mite work depending on what he used for glue. but still not some thing that I would want any ware near the person firing it.

[Ded10c]

Everybody does that. It's called DUCT tape. DUCT.

Also, paper is flammable. Guns use small quantities of explosive. I'd be very careful with a paper gun.

Besides, how do you propose to produce enough force to fire a bullet with a paper gun?

[Nielk1]

Everybody does that. It's called DUCT tape. DUCT.

Also, paper is flammable. Guns use small quantities of explosive. I'd be very careful with a paper gun.

Besides, how do you propose to produce enough force to fire a bullet with a paper gun?

AND NO! IT ISN'T USED ON DUCTS!

You use metal tape for that.

[Zenophas]

even if it works its not legal to build fire arms with out the proper lince in the US.

I think it does work.

[Psychedelic Rhino]

I have seen a cannon made out of duck tape so it mite work depending on what he used for glue.

What you see in those exhibitions of using a steel-band wrapped wood log (mythbusters), or a tape bound PVC tube, etc. is a low-yield black powder concoction of some kind.

This all falls back to what I mentioned at BZU once, and that is scale is often misunderstood in many aspects of physics.

Sure a paper tube might be able to fire a light-weight projectile (virtually nothing with a primer-only load). . . or a low-yield black powder with a bullet, but the gun barrel will certainly be ruined after one shot.

However, putting a modern cartridge loaded with its appropriate smokeless powder in a paper barrel will utterly destroy the barrel and endanger the shooter. A gun barrel is thick hardened steel for a reason.

Another aspect not discussed, is the rifling in the barrel. It's silly to even mention this since paper is SOOO unable to provide the shear force to spin up a bullet but I thought I'd throw it into the mix.

By the way, just FYI, but does anyone have any idea what a bullet spins at when leaving a rifled gun barrel? You might be shocked. . . .

[Psychedelic Rhino]

Anyone. . .anyone?

Bullets spin at insane RPMs. Some as high as a couple hundred thousand RPM.

To give some perspective on the relative speed, if you were to fictionally stop the bullet's forward speed of say, a .300 Win Mag, and retain the bullet's rotation or spin, and lay the bullet on a flat surface and measure the speed of it rolling. . .it would roll 225+ mph!

[APCs r Evil]

Oh that was an actual question? Wasn't sure.

On a related note, depending on the bullet's construction and the twist rate of the barrel, bullets can actually be spun apart mid-flight if the rpm is too high. The bullet literally disintegrates.

http://www.youtube.com/watch?v=GTJaNHjEa_k

[Psychedelic Rhino]

Yes, incredible. The g's are in the thousands.

I can figure out where the ductile failure would be for unjacketed lead rounds from the centripetal force or angular momentum, but a copper jacket adds a bit too much complexity for me to figure out since it's kind of hard to find out what the thickness of the jacket is and know the taper curve.

Amazing ultra high FPS video showing bullet impacts.