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View Full Version : Underwater : fact or complete fiction??



lottie
06-14-2009, 11:45 PM
Okay - So i've just watched Fools Gold starring Matthew McConaughey and Kate Hudson...quite a good film.

Anyway, i'm disgressing from the point in hand. In one scene, Matthew's character is chained to an anchor on the bottom of a sea bed (somewhere in the bahamas i think), with a normal gun nearby. He fires the gun to break the chains from his feet


Now the question is......Would a.)the gun still work under water and b.) would trajectory of the bullet being fired still be the same underwater???

Papa Bear
06-15-2009, 12:53 AM
The gun can fire underwater if the primer and the powder are still dry! The speed of the bullet would be even slower than one fired from the surface, because it has to push the water out of the barrel and the gas will not expand as fast due to cooling! I would say the bullet might travel a few feet! It would not have the power to cut hard chain steel! The lead would not cut it! So it is just in the movies, just like his ears clearing, or being able see to aim! Gotta love Hollywood!

The Publisher
06-15-2009, 01:20 AM
Yes, Papa is right.

Bullets are made of lead with a heavy copper jacket. Many cartridges have sealant where the bullet seats down into the case. Same goes for sealant on the case primer.

Most cartridges don't, and that would lead to water eventually getting into the primer and the powder over time, rendering them useless.

Round will travel about 3-10 feet underwater, depending on whether they are pistol or rifle cartridges and a few other variables.

A pistol round is never going to break a large steel chain. The mass of the chain is too great, so and the shape of the link is round, so a copper jacketed lead bullet would tend to deflect off of it or fragment to pieces.

Hollywood is sooooo fake. Like in the Survivor series in Brazil, pretty much every time they showed an epic panoramic clip, they dubbed in an American eagle shrill cry, what a total Hollywood sound effects cliche.



http://www.youtube.com/watch?v=q0KLQ1v41V4&feature=related

http://www.youtube.com/watch?v=eJTi2TjR1UQ&feature=PlayList&p=4C06FD7D21EF4582&index=62&playnext=2&playnext_from=PL

acelockco
06-15-2009, 01:29 PM
The gun can fire underwater if the primer and the powder are still dry!

And that is the main thing. I am sure the gun would work at a few feet depth, but I can't imagine the bullets not having water intrusion after much depth. The pressure would force the water into the bullet housing. Just think about all of the money we spend to have anything that is waterproof at depth (flashlights, camera housings, strobes, etc.). I seriously doubt the gun would work after a minute or two or at any real depth.

You are watching too much TV.

lottie
06-15-2009, 01:54 PM
You are watching too much TV.

Yeah - you got that right!!! Too much time on my hands and not enough to do!!

Thanks for all your replies about the bullet underwater, i didn't think it would work, but my mom asked the question and I wondered....

acelockco
06-16-2009, 12:08 AM
Yeah - you got that right!!! Too much time on my hands and not enough to do!!

Not enough to do, you live in paradise, get out there and do some F-ing diving! :mad2: :mad2: :mad2:

rubber chicken
06-16-2009, 11:21 AM
Whenever watching Hollywoods version of Scuba diving there is a little game that my friends and I like to play.

Get a bottle, (or two) of your favourite libation.
Whenever a diving mistake/impossibility occurs on screen, take a drink.

I have never seen the film in question but it sounds like another one that I will never get to see the end of :D

lottie
06-18-2009, 09:18 PM
Not enough to do, you live in paradise, get out there and do some F-ing diving! :mad2: :mad2: :mad2:

I would if i could, but i can't...and please try not to swear... :D

acelockco
06-19-2009, 02:11 PM
I would if i could, but i can't...and please try not to swear... :D

You can, I know it is tough to spend time away from your hubbie, but you deserve a little time to yourself once in a while. If money is an issue, there is plenty of snorkeling you can do as well. You said you already have lots of time on your hands.

And by the way, that was me trying not to swear :p

protogenxl
07-06-2009, 02:19 AM
I would have to think it would have to be a light chain and that the chain was threaded though the eyelet of the anchor several times. because for the bullet to transfer any real kinetic energy to the chain, the chain would have to be static and pulled tight against a material stronger than it's self.

it_mike
07-28-2009, 03:50 PM
A 9mm FMJ 'might' have enough momentum, if the chain was sufficiently secured.

Lest we forget, the momentum of the bullet is only part of the problem...

There is a reason why, even thought Glock sells parts to make their firearms (9mm only) fully operational under water, they recommend against it. The concussion could kill you. "The shock/pressure waves in water can really damage internal organs" - GlockFAQ

http://www.glockfaq.com/content.aspx?ckey=Glock_FAQ_General_Glock_Info#h2o

lottie
07-28-2009, 05:09 PM
A 9mm FMJ 'might' have enough momentum, if the chain was sufficiently secured.

Lest we forget, the momentum of the bullet is only part of the problem...

There is a reason why, even thought Glock sells parts to make their firearms (9mm only) fully operational under water, they recommend against it. The concussion could kill you. "The shock/pressure waves in water can really damage internal organs" - GlockFAQ

http://www.glockfaq.com/content.aspx?ckey=Glock_FAQ_General_Glock_Info#h2o

good point. Thanks for pointing it out!

I like the comment you noted- "The shock/pressure waves in water can really damage internal organs" - yeah it would, moreso if you've just been shot in the chest!! :D:D:D:D:D (sorry couldn't resist that :D)

it_mike
07-28-2009, 07:06 PM
:o:o Got me!! :rolleyes: