I took some high speed footage of a Autoloader firing underwater

Nicely done, thank you!

Very cool!

I've read the pistol bullet would leave the bbl before the slide cycle started,

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That can't happen. If the slide doesn't move until after the bullet leaves, the slide won't move. At least...not enough for you to notice.

Lemme go get a picture. Stand by.

Here is a very old fluroscope photo of a 1911 pistol caught in the firing phase. Note the position of the link, and the rear of the slide/frame alignment. Here...the base of the bullet is about an inch from the muzzle, and the slide appears to have moved approximately .075 inch...which is just about right.

The slide on a locked breech recoil operated pistol moves nominally 1/10th inch at bullet exit. The problem with high-speed videos is that they're too fast to see it. You really have to slow it down, and you have to have good resolution.

Well its good to know that if I'm going Scuba diving, I can rest easy if I bring a Ruger for CCW.

1911Tuner said:

That can't happen. If the slide doesn't move until after the bullet leaves, the slide won't move.

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That's an excellent point.

I think the earlier poster was referring to the basic concept of the short recoil auto loader, namely that the breech remains locked until the bbl pressure has dropped. And that's what I found surprising about the video--that video seems to show a certain amount of gas escaping at the breech prior to the exit of the bullet (ie, prior to the unlocking of the bbl from the slide)

If you study a few really slow videos, you'll notice that there's a considerable volume of gas that escapes not only from the breech...but also from the muzzle in front of the bullet.

The blow by gases are more apparent with jacketed bullets than with lead bullets that are soft enough to obturate early on and seal the bore. It's also why a lead bullet exits at a higher velocity than a jacketed bullet of the same mass with a given powder charge, and why higher peak pressures are also produced with lead bullets.

What a great video, very interesting. I'm surprised that the Ruger was able to chamber a round like that underwater. Ruger P95s are tanks.

These videos should provide some insight. Watch them all a few times.

http://www.trippresearch.com/tech/video.html

Thanks Tuner. The cut-away 1911 is just awesome! And you can clearly see that the slide/bbl move rearwards almost immediately.

That Tripp video also shows a similar out gassing @ the breech that the OP's video shows.

Watch the closeup cutaway 1911 again...and take note of the ammunition bouncing around in the magazine as the slide goes to battery. Also the bolt rebound on that AR15 before it settles down.

And you can clearly see that the slide/bbl move rearwards almost immediately.

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The slide starts to move at the same instant the bullet does, with the only delay being any headspace involved. If I know Virgil, that's probably limited to less than .005 inch. It would require some pretty sensitive equipment to see it or even detect it.

How much did your highspeed camera cost?

That was some cool footage. My heart would drop if my gun(s) were volunteered to be fired underwater. Even if nothing would break, I would still avoid any underwater shooting, too risky IMO.

dude that was awesome

but i wish you hadnt dont the stop motion when the pistol fired. id love to see the whole shot in slow mo

1911Tuner, Thanks for the information and pics. I'm still learning.
I wonder how slower or faster powders at different cartridge pressures affect the cycle? Seems like it would change even though time-wise it wouldn't be much.

Well I can tell the Self-Loader is a Ruger P95 and the revolver I can't make out what it is. But thats pretty cool, I love all the gas that comes from the barrel. I want to see what it looks like under water with a compensator.

Would it be possible to shoot with a suppressed gun underwater without it exploding? It'd be cool to compare it to unsuppressed.

well if you do try this at home make sure there are no air bubbles in the barrel and use something besides bushes for the backstop.

You have a new subscriber...

I imagine early Gasses by-passing the Bullet would be acting against the Water in the Barrel, ahead of the Bullet, to where, the Bullet itself might not even be touching Water untill some ways out past the Muzzle...

I imagine early Gasses by-passing the Bullet would be acting against the Water in the Barrel, ahead of the Bullet, to where, the Bullet itself might not even be touching Water untill some ways out past the Muzzle.

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And we've got ourselves an Outside-the-Box thinker in the crowd. The guy who notices that which is so obvious that most don't see it.

Kudos! You may advance to the front of the class.