High speed bullet strikes in gel and other stuff

[xs11jack]

OK this is a U-tube address that I don't know how to make into the link so you can just click on it and it goes to the location. Could use some help on how to do this.
Anyway, this location has a lot of high speed camera video stuff of bullets hitting gel and other stuff. Very interesting and educational.

https://www.youtube.com/watch?v=ycc7QkADCbA

Ole Jack
Oh hey, the address was turned into a link when I hit the post button, Cool!!!

[M-Tecs]

Here you go.


https://www.youtube.com/watch?v=ycc7QkADCbA

[Blackwater]

Thanks. What in the devil are those flashes of what looks like "fire" that seem to ignite in the wound cavity after the bullet has already passed through? Don't remember seeing those before. They're complete with puffs of smoke emitted as it tries to return to rest?

[mcdaniel.mac]

Thanks. What in the devil are those flashes of what looks like "fire" that seem to ignite in the wound cavity after the bullet has already passed through? Don't remember seeing those before. They're complete with puffs of smoke emitted as it tries to return to rest?
The bullet pulls a little air in before the 'entry wound' can close, which then carburetes with vaporized gel and then ignites, like a diesel engine. Heat and pressure, plus the oxygen, equals fire.

It's tough to see in anything but slow motion, and mostly happens with large bores moving quick enough but not too quick.

[GhostHawk]

When you are typing a message, look at the top of the frame. There are 4 important icons on the right.

First is the world with a chain, for links. So for a page where you want to post a link, copy the url, click that button, paste url into the window that pops up.

Next is for unlinking and I think that is new.
3rd one is for images, and it works great.

Last one looks like film, and it is for video's.

Simple, anyone can do it. Try it out in the testing area.
Same for

[imashooter2]

The bullet pulls a little air in before the 'entry wound' can close, which then carburetes with vaporized gel and then ignites, like a diesel engine. Heat and pressure, plus the oxygen, equals fire.

It's tough to see in anything but slow motion, and mostly happens with large bores moving quick enough but not too quick.

Well that is interesting. I wonder what portion of the wound channel reported in gel testing is actually from this explosion instead of the passage of the bullet?

[McFred]

Nothing is added to the 'wound channel' when you see that flash. There's no fuel being consumed when it lights up. It's merely a cavity of air being compressed hard and fast by the collapsing gelatin walls; it generates so much heat in an instant it lights up. This is similar to how diesel fuel will ignite in a truck engine. The compression of the air in the cylinder at top dead center is so hot it will light any fuel sprayed into the chamber.

The 'math' behind the mechanics can be derived from the Ideal Gas Law:
https://en.wikipedia.org/wiki/Ideal_gas_law

The same phenomenon generated by different means:
https://en.wikipedia.org/wiki/Sonoluminescence

[imashooter2]

Nothing is added to the 'wound channel' when you see that flash. There's no fuel being consumed when it lights up. It's merely a cavity of air being compressed hard and fast by the collapsing gelatin walls; it generates so much heat in an instant it lights up. This is similar to how diesel fuel will ignite in a truck engine. The compression of the air in the cylinder at top dead center is so hot it will light any fuel sprayed into the chamber.

The 'math' behind the mechanics can be derived from the Ideal Gas Law:
https://en.wikipedia.org/wiki/Ideal_gas_law

The same phenomenon generated by different means:
https://en.wikipedia.org/wiki/Sonoluminescence

Understood, but in the films it appears that this explosion sometimes expands the gelatin block more than the passage of the bullet. In my mind it calls the whole concept of gelatin testing into question.

[mcdaniel.mac]

Understood, but in the films it appears that this explosion sometimes expands the gelatin block more than the passage of the bullet. In my mind it calls the whole concept of gelatin testing into question.
It doesn't really, you can hold up a couple pencils if you don't have video editing tools and watch the maximum expansion relative to the frame. BrassFetcher videos are good for this in particular. While it will scorch the wound channel, the temporary cavity from initial entry is much bigger than the secondary expansion can be.

[xs11jack]

Ghosthawk, thank you, I actually copied your instructions to my computer.
Ole Jack

[Multigunner]

Here's another good video, though the music may not be to your taste.
Bullet impacts on metal and other materials filmed at one million frames per second.


https://www.youtube.com/watch?v=QfDoQwIAaXg

[Blackwater]

Thanks Mac and others. I'd just never seen that before. As you say, it must be something that only occurs within a fairly narrow set of parameters. Interesting. And Mac, I believe you must be right about bits of the gelatin being converted to vapor. This would give the air something to combine with the heat so as to make for ignition. Isn't "nature" amazing in both big and small ways?