bullets underwater

what would happen if a gun were fired underwater? How far would the bullet travel? Would it be deadly at a great distance? Would depth affect it’s movement? I’ve seen those cop shows and movies where they fire into water to get a new slug for ballistics, so I’m assuming water slows it right down to nothing pretty quick. Any help?

I think it’s safe to say that a handgun fired point-blank under water could be lethal, assuming the cartridges stayed watertight.

Beyond a yard or two, a lot of the energy would be gone. Depth would increase this effect (greater density).

If you’re lucky, one of those physics people will come along and crunch the numbers for you

Among other effects, the concussion would probably deafen you (assuming you were in the water with the gun), as sound moves considerably faster and more efficiently through water.


There are a slew of variables you’d have to set first for any accuracy, from what I know of ballistics. Are you talking handgun, shotgun or rifle? What caliber? Would the shotgun be firing buckshot or a slug?

A few things to consider. Depending on the caliber round and grain of the actual shot, you’ll have differing shock waves caried by the water. Ever hear a .357 fired? That’s the energy you hear through the air. Under water, if possible, you’d feel those waves. Get into a few hundred grains of propellant, and a slug might feel worse. Though no idea if it would hurt you.

The bullet under water would have a serioulsy shorter range. Water = greater resistance than air.

Of course, YMMV, since the rounds I shoot are too expensive to fire at anything I don’t intend to kill. Plus, they’re hollow-point, so under water my rounds would probably go about 8 inches.

I think Hammerback was trying to say that water doesn’t appreciably increase it’s density with depth. Pressure goes up, but density for all intents and purposes is the same. If the chamber of the gun was at the same pressure, I don’t think depth would affect the bullet’s trajectory much.

Bullets don’t go very far at all in water; the effective (likely to kill somebody) range of most bullets in water is only six to eight feet.

But, as duffer said, if your head and the gun are both underwater, you’re pretty much screwed – you’d definitely be deafened for awhile, possibly burst both eardrums, and have one hell of a headache. If it’s a largeish rifle caliber or .44 Magnum, you’ll probably have the standard concussion-induced flulike symptoms (ache all over, tired, generally feeling terrible) for awhile, too. I wouldn’t recommend shooting underwater.

I wouldn’t recommend shooting into open water, either, because bullets tend to ricochet off the surface if the angle’s wrong.
However, small water-filled plastic containers (soda bottles, etc) are quite fun to shoot, due to the uncompressible nature of the water. Or, for a dramatic gun safety demonstration (“this is your brain on hollowpoints”), use a bottle full of red Jell-O. :eek:

It looks like bad things happen.

That’s about the best answer anyone could hope for. Now I wonder what the actual damage would be firing a slug from a 12-ga. :eek:

Everyone is talking about handguns but the OP didn’t specify.

A little conjecture but a rifle with tape over the muzzle so the barrel did not fill with water would probaly fire without exploding. The bullet would of course slow down pretty quickly but most rifle bullets have much more velocity at the muzzle than handguns, typically 2-3x more, and spitzer type bullets have high sectional density and are very aerodynamic so they can go much farther and still retain enough energy to do some damage. Anyway, don’t try this at home.

psst…check post #5. We’re not limiting discussion to handguns.

From the link:

Never knew. Apparently the shock to the diver isn’t too great.

this thread may be of some interest to you. Shotguns in Space, and the replies I got cover firing underwater too. My first ever thread that. Knew it would come in useful one day.

From that link -

When I used to SCUBA dive, there was a thing called a bang-stick, it was a rod about 4 feet long with a firing chamber on the end. The one I used fired a .357 magnum slug, the “barrel” was about 3 or 4 inches long and worked by pushing it into whatever you wanted to shoot. It would blow a big fucking hole in a 55 gallon drum that we sank for the test. It was load, but not deafening. I believe you can also get bang-sticks in the 12 guage variety.


FYI, this page says sound doesn’t travel better through liquid when compared to air.

Unless the shooter’s firing FMJ rounds out of that underwater handgun, you’d have to be awfully close to get any kind of lethality out of it.

Hollowpoint handgun rounds don’t go far in water. They would probably expand almost instantly and only go about 18-24 inches at best, and then fall to the bottom.

Water-filled baggies or soda bottles are used in informal ammunition tests- it doesn’t take many to stop a non-FMJ handgun bullet. I think I read that it’s like 4-5 2-liter soda bottles worth, and that’s standing upright and shot from the side.

[slight hijack]
The New York Times had this article earlier this week about the sport of fish-shooting in Vermont (no barrels involved). Apparently you don’t shoot the fish, as this would result in fish-bits, so much as shoot directly in front of the fish; the concussion waves burst the fish’s swim bladder, killing it and causing it to float to the top of the pond.
[/slight hijack]

Related to this, my girlfriend once asked me about the plausibility of a scene in the Geena Davis movie The Long Kiss Goodnight, when Davis retrieves a handgun from an underwater corpse, rises to the surface with it, and shoots an enemy. During my research, I found out about the Glocks, but it turned out in the film they rigged a .25 (i.e. smaller than any Glock model I knew of) so it could fire blanks even when wet. The modification involved was not something you would do to a pistol normally, and it became impossible to fire actual bullets above the surface or below.

The Sydney Poiter/Tom Berenger movie Shoot to Kill ends with rather implausible underwater gunplay.