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Although the tests they perform on the show are not 100% accurate (then again is a test ever 100% accurate), tonight’s episode is about the myth where jumping into water will save you while being shot at. It seems that high velocity rounds fragment within a couple feet of water (even a .50BMG) causing no damage to you while a low velocity round can be lethal up to 8 feet of water. Now they tried the 9mm rounds shooting perpendicular to the water in a narrow enclosed tank, then breaking their test setup using a 12 gauge slug and were forced to shoot the high velocity rifle rounds at around 25 degrees into a swimming pool.

So is there a flaw to their testing, such as in the angle the bullet enters a major factor in how it will behave? The water displacement in a small tank vs. a swimming pool? Entering water as supersonic speeds is like the old saying, like hitting a brick wall? Anything else I missed?


On a side note they had to mention the sad fact of having to “borrow” the .50 BMG since it is illegal to purchase one in CA.
 

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Was bullet construction mentioned at all?
 

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Discussion Starter #3
From what I saw it was almost all FMJ bullets.

Quick rundown of what they shot:
9mm -FMJ
12 Gauge Slug - Lead
.50 Civil War bullet - Lead
.223 - FMJ
30-06 - FMJ
.50 BMG - FMJ
 

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I think there is a kernel of truth to the Mythbusters' finding.

Think of it this way: Water is an elastic medium. Normally when we hit water, the water can "get out of the way in time". But if you hit the water fast enough, the water's displacement is such that the water is inelastic and rigid.

Consider what happens when someone falls several thousand feet out of an airplane onto the ocean. It doesn't matter that the fall takes place onto water. The water's displacement is such that the fall might as well be on top of concrete.

Now if you fire a very fast bullet into water, at a certain point the same phenomenon takes place. The water cannot displace itself in time and the bullet behaves as if it hit a solid object. But a slow moving bullet may be able to slip through the water and be lethal.

I do know that African hunters do not like clients using very high velocity bullets at close range. High velocity bullets do not always penetrate through wet animal tissue as well as medium velocity bullets. I remember reading where 2400 fps is the magic number for maximum penetration. Perhaps it is no coincidence that so many really effective game cartridges use high sectional density bullets at 2400 fps.


Mad
 

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I just recently read an article stating the same thing as mad. They were trying to determine why the 6.5x55 swedish was such a good game cartridge when it is such a mild shooter. They said the 2400fps high section density bullets penetrated very effective. Supposedly the swede is very effective at taking moose and other large game.

MEL
 

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madgunsmith said:
Think of it this way: Water is an elastic medium. Normally when we hit water, the water can "get out of the way in time". But if you hit the water fast enough, the water's displacement is such that the water is inelastic and rigid.
I know a way you can test that! Belly flops anyone! :lol:

Try doing a belly flop low to the water....it doesnt hurt right? Now jump into the air and do one...now that hurts...and it feels more like hitting something solid to!

StealTh
 

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Speaking of water... I can't float. Does anyone else have this problem...as soon as i stop treading...even with a full breath of air....down I go.

-Brian Shields
 

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dead_I_5_0 said:
Speaking of water... I can't float. Does anyone else have this problem...as soon as i stop treading...even with a full breath of air....down I go.

-Brian Shields
Body fat has a lower density than water, muscle tissue has a higher density than water. Sounds to me like you don't have much body fat. If you want to float, eat more and excersise less. Problem solved.

John
 

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mele said:
very interesting.... can you elaborate on how each of those loads did?

MEL
The 9mm went down to 8 feet. So did the slug.

The 223, 7.62, and .50BMG would only penetrate or hit the ballistics jello at 3 feet. None of the rounds made it past 4" of jello though. The 223 was just stuck in at the tip. The 7.62 was about 4" into it, and the 50 only had a fragment or two touch the jelly.
 

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!

Hk Made that gun a while ago that would fire underwater and the only way they could even get a effective range of 15 meters was by using some kind of 7.62 dart round.

Should make for some fun tests. The BOX of truth website did some similar tests with water jugs but using handguns only.
http://www.theboxotruth.com/bot13.htm
 

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Recoil said:
I do not believe you in the slightest. Get a digital camcorder and record yourself doing this experiment. Then post it so we may judge the results for ourselves. :wink:
Haha :lol:

Wish i would have had a digital camera at summer camp on friday, we had water sports in the lake and one of them was "scoutmaster's belly flop". I would have had a perfect example of a low belly flop, and a high one (the high one was some 300 pound guy, that stood on the top of the ladder on the dock, and jumped from at least 6 feet and did a belly flop...OUCH! :shock: )

StealTh
 

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Unless you've got lead in your rear.
now recoil, I've been called dumb *** and fat *** but lead ***??? that's a new one! :lol:

on the subject of things being shot into the water...i've been welted by a bb gun while I was under water...it was shot from outside the swimming pool at me. i was barely under the surface but it still maintained enough velocity to hurt like a mother...

-Brian Shields[/quote]
 

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When I was in college we were messing around in a pool after some basic (like very basic) lifeguard training, and one of the dudes in my class decided he was gonna jump the high diving board. I dunno how high it was, but I would say 18 feet, about the height of three men. Preoccupied by lookin' cool for the ladies, he tripped over his own big feet and bellyflopped it. The slap sounded like a 12 guage and everyone in the building came to see what happed. I've never seen welts like that before lol.

I want to know how far into the water a good old 45-70 405 grain hard cast lead round at 1880 FPS would go.
 

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I was talking to a coworker about this....and he was saying something about the way the 9mm rounds were hitting. He said the exit wound was as small as the entrance, which led him to believe that they were using ball ammo. I wonder if they were using ball ammo in the rest of the loads?
 
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