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Can A Handgun Be Fired Underwater? What Happens if You Do?

We’ve all seen the action movies where the protagonist dives into a body of water to escape their pursuers, only for the firefight to continue under the surface. While holding their breath, they fire round after round at the enemy, and you see bullets piercing through the liquid between the rivals. With the help of special effects, it looks pretty epic; but is it even possible?

Most handguns, particularly modern models, can be fired underwater. However, doing so will significantly diminish the shot’s accuracy and speed, as well as potentially damage essential components.

In this article, we will explain how handguns fire underwater and how this affects the firearm and shot. We will also provide tips regarding what to do if your handgun is submerged to minimize damage and avert potential harm to yourself or others.

What Happens When You Fire a Handgun Underwater?

While it isn’t recommended, it is possible to fire a modern handgun underwater, but you won’t find the process, conditions, and results equivalent to firing it through the atmosphere.

Once submerged, the handgun’s barrel will likely fill with water. This increases the pressure and resistance within the barrel that its loaded ammunition must overcome upon firing in order to exit.

Depending on the barrel’s length, the bullet’s weight, and other factors, the water’s presence might prevent the bullet from firing at all and cause serious complications that might even put the user’s safety at risk.

If the bullet is able to exit the handgun, you’ll likely notice that its speed and trajectory are immediately affected. Because water is 800% more dense than air, any round fired in these conditions will have a significantly reduced range.

Most bullets won’t travel more than 5-10 feet, depending on the firearm, but it is not uncommon for them to stop immediately after entering the water.

  • The water’s increased density and weight also push the bullet downward almost instantly, rather than allowing it to travel straight for several feet.
  • The extreme heat and low pressure that occurs during the firing process cause water to create a partial vacuum around the bullet and even boil.

The culmination of these effects makes it extremely difficult to accurately shoot a modern handgun underwater, especially if it is not designed for these conditions.

Here’s a cool video answering the question, will a gun fire underwater:

I use either Brownells, Palmetto State Armory, or Optics Planet to buy parts, that way I always know what I’m getting and that it will actually show up.

Can Antique Handguns Fire Underwater?

If there’s anything worse than attempting to shoot your brand-new modern handgun underwater, it’s testing this shot with an antique.

It is near impossible to fire a handgun that predates the 1900s underwater. In the early ages of firearms, even shooting in the rain was near impossible due to the fact that black gun powder loaded as ammunition cannot burn when wet.

This type of ammunition was gradually replaced in the late 1800s, but the materials and designs of early 1900s handguns mean that they are also unlikely to even fire when submerged.

Modern handguns can do this to some degree because they are equipped with water-resistant ammunition and feature innovative designs that will allow them to fire as they would on land.

Do Underwater Handguns Exist?

Anyone looking for a weapon to use for self-defense or hunting underwater will usually opt for a harpoon, a spear, or even just a standard fishing pole. But what if you’re in a high-stakes scenario like military combat? Are there guns designed to operate optimally in these unique conditions?

Yes! Underwater firearms do exist, but you are unlikely to find them in your standard gun shop. These weapons are often utilized by U.S. special forces and other authorized personnel.

They feature revolutionary components and bullet designs that allow their rounds to create a supercavitation effect (source: once fired. The bullets, specifically, have a nose that creates a small air bubble in front of the projectile as it moves. This air bubble significantly reduces drag on the bullet, allowing it to travel at higher speeds.

Of course, this is just one part of the equation. The firearms are also fitted with waterproof materials and components designed to allow increased range and accuracy underwater. Most of these firearms used today are rifles, like the APS and ADS Amphibious Rifle, but handguns like the SPP-1 and HK P11 exist.

What to Do If Your Handgun Is Submerged Underwater

Submerging your handgun underwater is arguably one of the worst things you can do for its integrity, apart from going the extra mile and actually firing it in these conditions.

Most guns are made with water-resistant or even waterproof materials that allow them to withstand moderate amounts of moisture they might be exposed to from snow, rain, or other elements. However, these will not keep it safe once it is underwater.

If your handgun is ever submerged in water, the first thing you’ll want to do is to remove it immediately and try to dry all of its components thoroughly and as quickly as possible.

Start by disassembling your handgun and wiping it down using a super absorbent, microfiber towel or water displacing oil. While taking your gun apart, look for any apparent signs of damage that might have occurred upon firing or submersion. You can then leave the components out to air dry in a warm, well-ventilated room.

Your biggest threat for damage here will be rust, which is why it is crucial to remove as much moisture as you can. If rust does appear on any of your pieces, you can attempt to remove it using a light oil and a slightly abrasive brush (preferably copper) or a piece of steel wool.

I use either Brownells, Palmetto State Armory, or Optics Planet to buy parts, that way I always know what I’m getting and that it will actually show up.

Final Thoughts

Firing a handgun underwater might be exciting in theory, but in reality, it isn’t recommended. Not only will your handgun be less effective once submerged due to the water’s increased weight and density, but you will also likely damage your gun in the process. There are some firearms that are specifically designed for these conditions, but they are rarely available for public purchase.