Just curious, How deep would water have to be in order to stop a bullet? Or, at least, slow it down enough so that it does not damage the opposite side of the water container? Assuming a plastic container.

Good question - often wondered the same myself.

5.56x45 55gr ball @2800fps

9mm para 124gr ball @ 1100fps

[url]http://www.ar15.com/forums/topic.html?id=119900[/url]

Some equations from the Fluid Dynamics book suggest about 18ft for the 5.56x45 and about 14ft for 9x19 (using numbers from Tate's post). Of course, this does not account for breakup of 5.56 ammo in soft targerts. Also, fluid dynamics can be a pretty uncertain science, so don't go using these numbers to set up backstops or anything.

Less than 3' for .22LR. As part of disposing of an old pool,unsuccessful attempts were made to drain it.

18 and 14 Feet! holy shit. I'm certainly no ballistics expert but that sounds like one hell of a lot of water to stop a bullet.

I don't know the answer, but I think we need some more research on this one.

Mike

Well if the techs from SPR got it right it must take quite a bit to stop an 8mm.

That underwater scene still gives me the heebe geebies!

True, but I always had a problem with that scene.  It seemed to me like they wouldn't penetrate that far, in fact, from the angle they were firing, I wouldn't be surprised if the rounds skipped off the water.

Mike

Was this shooting at an above-ground pool from the outside? If it has to penetrate the side of the pool first, that changes things a bit

This is what i was thinking.
We bought an Easy Set pool last year (about three feet deep x eighteen foot diameter) and I have been curious about what would happen if I shot into it.
Would it stop the bullet, 9mm or .45acp jhp, or would I have to buy a new pool?
Would the bullets expand or not?
It's one of those things that I know I'm going to do eventually, just 'cause.

From the NRA Firearms Fact Book:



I recognize that there is a big difference between the bullet stopping in the water, and the bullet not penetrating a 1 inch board, but thought I'd throw this out just for info...

The  tanks I've seen in forensics labs are only about 10-12 ft. long. This amount of plain old room temp water was enough to keep all projectiles from contacting the tank walls.

Might want to double-check those numbers.  I read an article from Richard Lee (of Lee Precision) that said he recovered bullets from his 22-250 by shooting them straight down into his backyard pool.  He said the bullet was traveling at about 4000 fps.  If his faster 5.56mm bullets were stopped by a backyard pool, I don't think the slower 5.56x45 would require 14 feet of water.z

the tanks police labs use to do ballistics testing in are about 3 or four feet high and 5 feet long

I recall an article from [b]precision shooting April-May 1997 "The super box".[/b]

On how the [B]old timers, c.1900[/b] used to recover bullets using one of Dr. Franklin W. Mann's recovery boxes

Basically what it was is a wooden box about 10' long with paper baffles spaced at so many feet and fill the thing up with heavily oiled sawdust.

In the article the they shot a few magnum velocity projectiles [b]not listed in the article[/b] 1300-1400fps in it without a hicup at 50'

They also mentioned they did preliminary tests on .22 cal jacketed hollow and soft point varmint bullets traveling at the reduced velocity found in the range tables at 400-500 yards were rather disappointing [red]expansion wise[/red].

In the may issue they were going to try higher velocity tests simulating closer ranges then big game bullets.

if you can find these magazines its an interesting read to say the least.

Yea  we do that now with phone books,give me 36 inches of water and I would think you would be below some small arms fire,but money walks and bullshit talks and i don't want you shooting at my ass in three feet of water,


Just kidding   All my  bullets belong to me!


Bob[:D]

If I remember correctly, water penetration depth is very roughly 2.25-2.5 times gelatin penetration depth (better check on this, before building
anything based on this value). 5.56x45mm gets only about 14" of gelatin penetration (due to fragmentation).
(7.62x39mm is about 30 inches). So to be safe you'd need a tank of water 6-7ft long to slow down 7.62x39mm to "safe" energy levels

Here is me talking out of my @$$.

Water is 800 times denser than air.  In order for a bullet to travel through water very far, it must be stable.  So it must be a [b]LOT[/b] more stable than is actually is.  

In reality, a bullet couldn't be stabilied that much, it would fly apart.  Therefore, when a bullet hits water, it destabilizes instantly, and slows down very fast due to water resistance.  This probably explains the small penetration depth, and the relatively weak penetration with pine blocks.

Ask Tatjana...  She could tell you for sure!

Water is the best on  this planet anyway,because its almost non compressible.  Firemen jump off the engine wrap the hose around the plug and wait till the engine gets close to the fire.

Then they hook up to the plug,and try to outguess wnen the officer or driver will put the hose clamp on the line then he slowly opens the hydrant as 2000ft of hose are laid to the fire hose clamp.  As water is non compressible on this planet and air is compressible.


The officer or driver releases the hose clamp only after the Captian or other firefighters have entered the building with dry line and scott air pacts on.  Then it's all about compressed  air again.

When you confront the fire you slowly bleed off the air in your line,(or it's like pulling the oxygen lever on a cutting torch)  and then you fight the fire.    Wood takes about 400 deg to put off flammable vapors,and burns at about 750 deg.

So when you hit it with a fog line the water hits it in a mist turns to steam  212 deg and the fire goes out .   The conversion table is one gallon of water equals 1200 gal steam, so while it doesn't seem  like the fire caption knows what is really going on it is possible to just open the door to a confined fire wave the fog nozzel around a couple of times and the fire goes out by simple conversion,  


But the whole point of this is to tell you if your par-chute didn't open ,you would be better off hitting concrete than water.  As cocreate is compressible water is not.   Thats why bullets get real useless in it.



 Bob  [:D]

This test was conducted several years ago using a CCI Stinger .22 LR.  When fired at point blank range horizontally into a 15" wide plastic container filled with water, the hollowpoint projectile never made it to the other side.  Only small remains of the bullet were recovered including a ring of copper plated lead.

As someone who has dealt in concrete for a long time, I think I am gonna have to take the water option.....Call me stupid, and Im sure from a parachute it much dont matter but....

Years ago I was really into the bullet testing thing, and vertically fired handgun bullets into a  blue plastic 55 gal drum filled with water while standing over it on the backyard deck. Several things emerged from this testing. .22 and 380 ACP bullets out of short barrelled pistols do expand reliably, 44 special lead hollow points get big enough to use as a dinner plate, and 357 180 grain bullets will get you very wet as the water vents twice your height out of the bunghole.  None of them ever penetrated or even dented the bottom of the barrel. Next time i'll get two barrels and a battery operated bilge pump and transfer the water back and forth,  that way I won't flood the whole yard again.

As someone who has smacked his head on concrete many a time, I think I am gonna have to take the water option also...

I'll take that 0.1% chance of living over that 0.0% chance anyday.