M14 blast wave picture:

[Lucky]

Some old reading and saw this:

The curly line isn't a hair on the lens, it's the sound wave.

 

[1 old 0311]

Great pic.

 

[Peter M. Eick]

Ya know whats interesting is that you don't see the gas coming down out of the cylinder. I would have expected that by the time the bullet got to where it is you would be venting gas down out of the cylinder and see the action operating.

 

[Vityaz]

That's actually the first thing I looked for. Gas system could be turned off though.

 

[Arkie]

Now that's pretty neat!

They even caught the bullet in flight. Just barely. LOL

 

[RecoilRob]

Looks like they have a couple of transducers plugged into the gas system. Maybe to trigger the photo?

 

[jakeswensonmt]

You can even see the echo coming back up off the table. Wow.

 

[Ian]

No magazine, either. Interesting pic!

 

[JesseL]

What surprises me is that the bullet is apparently only moving a little less than twice as fast as the sound wave. Isn't that a little slow for a 7.62x51

 

[General Geoff]

2800fps is nominally ~1900mph, or mach 2.7-ish.


edit; we don't know what kind of atmosphere the photo was taken in. It could skew the speed of sound drastically.

 

[Sriracha]

Cool picture!
Btw, the picture shows a shockwave, which can move much faster than the speed of sound.

- Sr.

 

[Lucky]

Interesting, something to contemplate. Can you elaborate? It makes sense yet it doesn't.

 

[Wes Janson]

It occurs to me offhand that the shockwave might have begun before the bullet left the barrel?