Finally realized why

[HagarTheHorrible]

I was watching a program last night, "Attack of the Zeppelins" on channel 4 (UK), well, the odd bits of it anyway, and they gave a very good demonstration of incendiary bullets.

 

I know I'm a bit thick at times but I just hadn't really thought about why they made a corkscrew shaped smoke trail, I thought it was all to do with gun camera oscillation, or some such, for some obscure reason.

 

Evidently, the weep hole for the phosphorous filling is in the side of the bullet.  As the bullet is fired the heat melts the solder in the weep hole thus letting the phosphorous leak out and ignite.  Obviously when the bullet is fired from a rifled barrel it spins, the phosphorous as it ignites, leaves a trail of smoke and because its coming out of the side of a spinning bullet it leaves a corkscrew shaped smoke trail, simple really when you think about it. 

 

I had always imagined the weep hole was in the back of the bullet which presumably would have left a straight smoke trail.

[FuriousMeow]

Not the same thing raaaid, not the same thing at all. All rounds come out of a rifled barrel, that causes spin around the direction of flight axis, and the port of exhaust of tracer/incendiary rounds is on the side. So the spin from the rifled barrel causes the gases expelled to cause a spiral. Yes, 109s had that in their larger caliber weapons and can be seen in many a gun cam footage. If the exhaust port were in the rear, the energy from the gun powder to cause the projectile to project would enter into the hole in the rear lessening optimal projection and quite possibly blowing the material out of the round itself.

 

Also, this is somewhat of an interesting thread: http://forums.ubi.com/showthread.php/481111-have-you-ever-heard-of-eccentric-bullets-Forums

 

Never forget the Ginebra convention!

Edited August 27, 2013 by FuriousMeow

[Jaws2002]

Tracers:

 

 

 

 

Incendiaries:

 

 

 

 

API:

 

 

Check this page:

 

http://www.ar15.com/ammo/project/Ammo_Cross_Sections/index.htm#8mm_APIT

 

 

It has a good collection of different rounds and it explains how they work.

there are many different kinds of incendiary and tracer bullets, depending on what they tried to shoot with them. But in beneral, the tracer is filled in the rear of the bullet so it can be ignited by the propelant and incendiary bullets are filled in the tip and they ignite on impact, whenthe bullet hits a hard surface.

There are many variation, but this are the most common ones.

Edited August 28, 2013 by Jaws2002