Posted on 06/25/2013 12:34:29 PM PDT by servo1969
Previously SmarterEveryDay filmed pistols being fired underwater with a high-speed camera. This time they have gone a little bigger. Using a custom-made stand an AK-47 variant is first filmed being fired in the air. Then the rifle is fired while completely submerged underwater.
So here's the science question: Does the bolt cycle faster in the air or underwater? Why?
Make your guess and then watch.
http://www.youtube.com/watch?v=W5K6YymPe_M
It cycles faster in the air.
There is way less impedance in the air than underwater.
Otherwise we would be in a Kevin Costner film....
Wild guess would be, action is faster under water. Since water will not compress and air will. Therefore the action would move faster. But velocity and range of projectile, would suffer greatly due to increased resistance of water over air.
I got it right! It’s faster underwater for the same reason the compression ratio on an engine is raised slightly on a rainy day.
In air, the piston does not start backwards until the bullet is past the piston port. In water, the the piston starts back immediately.
Exactly. But I didn’t say it that way. But we agree faster cycle under water.
Interesting.
Here is the really really important question::: So what?
The rifle/carbine & round is ineffective underwater water anyway.
I can’t believe I am actually wasting time with this silliness.
Oh, Alright....Furthermore, case adhesion in the chamber during this moment when (maybe) the bullet is forcing water into the port etc, would overcome any incidental forces generated by the water being pushed out of the way of the bullet, before the bullet passes the gas port anyway, keeping the bolt locked. I doubt your suggested answer is correct, and no, I do not have a counter response, as it is a silly exercise to begin with.
I think we are supposed to “shoot fish in a barrel”, but not with the AK variant in the barrel as well....
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