If you were 5 ft under water, which would you rather be shot at with?

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The Real Hawkeye

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A .50 BMG or a 9mm?

According to Myth Busters, the fmj 9mm would be lethal at that distance while the .50, even with armor piercing rounds, would shatter into harmless tinsel within three feet. The .223 and .30-06 performed exactly like the .50 BMG, shattering into harmless tinsel within just a couple of feet, using only fmj in all cases. The key to survival under water against gun fire, it seems, is supersonic bullets.
 
One problem with the way they conducted the test is that the 9mm was fired perpendicular to the water, where the .50 was fired at an angle. The shearing force was in no way comparable.
 
Back in the early 1980s, I fired a 9mm JHP round into a swimming pool where the water was only about three feet. The round did not pierce the vinal, and was resting at the bottom fully mushroomed, with 100% of its original weight.
 
The other factor in addition to angle of impact is range from muzzle to water - velocity. A standard .30 or .50 FMJ might go to pieces fired from a distance of a few yards; what about from greater distances?

I do not think a standard 9x19mm roundnose FMJ will sustain injury creating velocity in water for very long. Make an interesting test, maybe submerge some frame boxes containing evenly separated layers of stretched fabric, at various measured depths, and hammer away at them with a couple of boxes of FMJ and see how deep one has to be to avoid getting hurt.
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i don't have much faith in the mythbusters test. They changed the expirement in the middle of the test.
 
I guess no one here has ever shot fish.. A little pass time in Scott County Va in the Clinch river during March through May.
 
Watching it again right now, the test is not the same. Either way the water dissapates energy of either rounds extremely well and at 5ft underwater (still wundering why I am there) I would not want to be shot at with either but to play along I would want to get shot with the 9mm.
 
somebody should post something on the mythbuster forums about how their tests were conducted differently, they might decide to re-do it
 
The only thing that consistently bugs me about that episode is how they talk about the M1 Garand without ever mentioning what caliber it is. As if somehow a .30-06 round fired from the legendary M1 would perform differently from every other .30-06 rifle on the planet. :rolleyes:

I guess that's a fairly common misconception though. I'm always surprised when I'm talking to non-gun folks and they think there's a difference between the damage done by two different guns of identical caliber. I'm always trying to tell them "The gun makes it more or less likely you'll hit what you're aiming at. Once you've hit it, the gun the shot came from doesn't matter anymore. At that point, it's all about the bullet."
 
Our 'Mythbuster' friends obviously don't know the difference between FMJ and AP. Yes, all AP are FMJ but NOT the other way around.

The 50BMG round they fired could not have been AP. Nope, no way. They held it up and called it so, but it was just a lead cored FMJ and behaved exactly the same as the smaller caliber rounds. Which makes sense. Same construction, same relative jacket thickness, same velocity= same performance.

I would propose that the show Producers re-do the 50 part and I'll gladly provide the AP rounds to show them that they will most certainly NOT disintegrate inside of 3 feet. Heck, even the mild steel cored Ball round would stay together and hurt things badly a yard under the water.
 
a lot of you made good points as to why the .50 cal did not penetrate like the 9mm in their test. one reason, i think chipperman said also, is that the 9mm was taken at a steeper angle.

another reason, i think, is because the 9mm is rounded whereas the .50 is pointed, so the .50, at the angle it was fired, essentially hit the water more towards the side where it has a flat surface. obviously, the ball hitting on a flat surface will shatter the bullet because it will not have the penetrating capability that it would if it hit with the tip. the 9mm, on the other hand, would penetrate better because it is more ball-like in the front, plus it was shot at a steeper angle. put it together, and you get the 9mm going further than the .50.
 
The sonic velocity in air has no bearing on bullet performance in this case. The rifle bullets are moving much faster than the pistol bullets and the force applied to a bullet from the water is exponentially higher. Much, much higher in the case of rifle bullets. I just got done firing the WWB 115gr 9x19mm in gelatin and the bullet turned on it's side at about 8" penetration depth, but did not break up. Try the same trick with an M855 or a .50BMG A-Max in gelatin and the performance is about the same - except the rifle bullets cannot stand up to the pressure and break into many pieces.

If I were 5ft underwater, I would like the rifle bullet a lot more than the pistol bullet - said 9x19mm FMJ penetrated 16" of gelatin, 9" of water and 12" of bullet arresting box (roughly 16" of gelatin equivalent). I'm not trying to close down the thread, either, just wanted to share what I know. :)
 
"a difference between the damage done by two different guns of identical caliber"
Sounds like an idea coming from computer games... where a bolt-action 30-06 Springfield will be a one-shot-kill to the torso, but a 30-06 Garand can't kill unless there's two to the torso. And a .45 ACP revolver is a one-shot-stop, but a 1911 takes two.
 
If you're using lead-cored jacketed ammo, the lower velocity rounds will penetrate better because the high velocity stuff will tend to fragment on impact with the water's surface.

If you go to true AP, the results will be more intuitive.
 
While I agree that they changed their experiement midstream I do not think that this materially changed the performance of the rounds tested.

The reason the 9mm did best was simply because it remained intact. The others did not. Shearing force has nothing to do with it. Once the bullet scatters the smaller pieces stop much more readily because the energy dissipation required per piece is much lower.

It's like comparing the stopping force required to stop a Cadillac Fleetwood to the stopping force required to stop a VW Bug. All things being equal, smaller masses just stop more quickly from a given velocity and equal braking than larger ones.
s
 
280 beat me to it

Water pistol. As much as I like the show I will not be the guinney pig for this particular test.:p
 
While I agree that they changed their experiement midstream I do not think that this materially changed the performance of the rounds tested.
Click to expand...

Right, regardless of the angle, the .50 as well as the other rifle rounds, were hitting the water destabilizing and turning broadside as a result as would happen in soft tissue, and became structurally disconbobulated (fragmented) in the process. This is part of what happens when the projectile travels at such velocities and is destabilized where the heavier tail end tries to switch to the lead end when hitting something 1000 times more dense than air, water.

Regardless of the angle, the relatively thick/stump shaped 9mm rounds were NOT going to fragment, and while destabiliized (tumbling), the tumble not affecting the loss of energy anything like flying apart does on the rifle rounds, hence getting better penetration.

I would feel much safer from a .50 BMG than a 9mm at 5 ft of depth.
 
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