A once and for all "guns underwater" thread...


May 25, 2004, 11:24 PM
OK, we've all seen it in movies a couple dozen times, heard rumors about "which guns will shoot underwater", etc...

Lets get some actual facts going here. What is the real story about how water affects the operation of modern combat oriented firearms? If you submerge your autoloading rifle or handgun, is it ready for action the second after you pull it out of the water? Will any gun actually cycle under water or while full of water immediately after being submerged? I'm sure the questions will get more specific, but this is a start. Have at it.

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May 26, 2004, 12:12 AM
Sounds like mulitple questions there.

First and foremost, I have never attempted to fire a firearm underwater. I don't see much use, but ok. I can see use for needing to fire once you emerge from the water, but, since I am not a SEAL, chances for that are very, very very slim.

Will a firearm be useable right out of the water? Yes, if you drain the water out of the barrel. It will fire if there is water inside the barrel, but the accuracy would be gone. I am suret there are more reasons why you needs to drain the water out, but they elude me.

Certain firearms will cycle underwater. Any gun will fire underwater, once. Some you can fire more than once. Revolvers I imagine. I know Glocks are capable of this, and they sell maritime spring cups for their pistols.

Other things to consider though are this,

1. The barrel needs to fill with water before you shoot underwater.
2. Don't use HP, since they are designed to expand in fluid, and there is fluid in the barell.
3. Wear hearing protection. By all acounts, shooting underwater is LOUD.


Also, if you shoot at a fish underwater, do you need a fishing license, a hunting license, or both?

May 26, 2004, 12:55 AM
There's info on this:


If you HAVE to fire underwater, you prolly want one of these:

http://www.rusarm.ru/exprod.htm (click Special Forces, then click on eith of the first 2 choices)

And Lenny Magill sells a video on this topic:


May 26, 2004, 05:28 AM
I've fired my Beretta Jetfire (.25ACP) in the spa, and yes, the gun did cycle underwater. I only fired one shot, but the gun did eject the spent casing and loaded a new one into the chamber. Not bad, considering the Jetfire does not have an extractor and relys on blowback to eject the round.

May 26, 2004, 06:08 AM
Defending yourself against fearless protozoa perhaps?
Did the bullet impact anything in the spa?
Detail please.

May 26, 2004, 07:07 AM

I'd love to see the black box on that one - I've done a lot of things in a spa......

My understanding is that the density of water poses problems in the travel of the projectile and also the functioning of semi-auto. There are stories for which I vouch not of a major east coast SWAT team hunting grouper after SCUBA drills and allegedly a major convention that had an emphasis on weapons had conflicts with hotel management over gun tests in the swimming pool. The fact that they occured at 3 AM and the researchers were drunk may have been a factor.

I'd be real cautious about acting on unverified info about this subject. The possibility for damage to the weapon and more importantly the swimmer is real.

May 26, 2004, 07:12 AM
Whoops, it was a jacuzzi, not a spa! Uh, I think maybe 5' in diameter? I dunno...

But no, the bullet did not even make it to the other side nor did it caus eany damage. I was above water when I did this, stuck my hand underwater at one side of the jacuzzi, and fired.

The bullet was recovered and apart from the rifling marks, undamaged (it was FMJ).

May 26, 2004, 08:16 AM
So how does water in the barrel not cause a pressure spike when a round is fired?

May 26, 2004, 10:46 AM
I have tried some crazy things in the past, but doubt I would ever try shooting any of my guns underwater.

Zach S
May 26, 2004, 11:26 AM
I have no doubt that my 1911s will cycle fine underwater. I also have no intention of finding out if they will or not. I do, however, normally keep my second (or third) mag loaded with ball ammo just in case...

Personally, I think if I got into a gunfight underwater I would have had to do a lot of things wrong and it would be a "do as much as I can before I die" situation, and the thought gun possably blowing up in my hand wont matter when I'm drowning...

May 26, 2004, 12:41 PM
I'm not planning to get into a fight underwater... I'm just curious about how the water will affect the operation of different guns. How much does it take to stop them from running? Hard rain? brief submersion?

How will a gun fire with water in the barrel? It seems that the extra weight of the water would cause a chamber pressure spike that could destroy the gun.

May 26, 2004, 02:46 PM
One think I have wondered about firing a gun under water...

Doesn't shooting with a barrel full of water have a risk for barrel rupture? While a liquid, the water is relatively incompressible and will have to move out of the way of the bullet. It effectively acts as a barrel obstruction.

Check out this HK underwater gun (http://www.hkpro.com/peleven.htm), the P11. 5 shots and has to be reloaded at the factory.



May 26, 2004, 04:00 PM
What is that 5 barrel gun that she has?

oh... nevermind. I clicked on the underwatergun link...

May 26, 2004, 04:56 PM
DON'T EVEN THINK ABOUT IT. IT IS CALLED AN OBSTRUCTED BARREL. Especially dangerous if you are talking about a rifle.
I agree with ttbadboy about pressure spike. I don't want to be around a gun fired with a barrel full of water, either in or out of a jacuzzi. You might get away with a pistol, with a short barrel. It is done often with powerheads underwater, but that is basically no barrel beyond the bullet. You get dangerous pressure spikes with a bullet a few grains too heavy for the load, so how you gonna push a barrel full of water that weighs many times the bullet weight.
Gun would probably fire ok with water drained out, and only a "wet" barrel, but even then it could be dangerous IMO.

May 26, 2004, 05:54 PM
Guys, just found the video on my hard drive that shows someone shooting two rounds out of a Glock in a lake somewhere.


May 26, 2004, 06:06 PM
Finally, a reason tobuy a Glock....

Let's shoot some fish!

May 26, 2004, 07:25 PM
I dont know about Rifles or Shotguns...

However, shooting a handgun underwater (while NOT a good idea) has been done before...The reason that it can be done is simple...Atmostpheric presure...The inside of the barrel and the outside has the same presure...Either in water or in air, it has to have the same pressure...If the Barrel is full of water and the outside of the gun is in the air, you have an obstucted barrel...KB's are what happens then..

I read the above somewhere in a gun rag written by Chuck Taylor...While I respect his opinion, I do not advise the above to be done unless in a controlled enviroment....BTW, he was shooting a Modified G17...I think Glockworks has written an article on there website about this...

May 27, 2004, 07:52 AM
Seems to me that many moons ago, that while lounging around the motel pool after a big time IPSC match, that several of IPSC's head dudes and big name shooters got to talking about this very subject. As I recall someone allegedly fetched their 1911 carry .45 and put all theory to rest by firing off several rounds under water.

Maybe its just one of those rumors that got floated around.

May 27, 2004, 08:15 AM
Wow... those guys need to reduce their beer intake after the matches. They were poping off rounds in the motel pool? :eek:

Personally, I don't see how an autoloader could function underwater. It just seems that the water would resist the movement of the action too much. And wouldn't the recoil characteristics of a gun underwater be changed? Wouldn't this affect recoil operated handguns especially?

May 27, 2004, 10:43 AM
Do a Web search and you'll find several pages on the subject. At least one site deails using a G17 (with the maritime spring cups) to penetrate plywood 11' away. The key is that the barrel must be completely full of water, don't use hollowpoints, and DON'T put your ears underwater.

May 27, 2004, 01:09 PM

Your simple reasoning is wrong. Yes, the pressure will be the same inside and outside the gun if you submerge it, but that is irrelevant for this discussion. Think about it, under 1" of water, the pressure increase over atmospheric pressure is negligible. The issue of an obstructed barrel has nothing to do with pressure and everything to do with viscocity/mass. A bullet + 5" column of air is not goint to resist acceleration like a bullet + 5" column of water. Not even close.

HOWEVER, this doesn't mean that all guns fired underwater will blow up, I've seen pictures of several revolvers/pistols that have been fired repeatedly with a bullet lodged in the barrel, and all the rounds fired afterwards built up behind. I would expect a high pressure handgun (e.g. 10mm or .454 Casull) or especially a rifle or shotgun to explode if fired under water.

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