Introduction: why this question worries gun owners and physics enthusiasts

The Kalashnikov assault rifle is a legendary weapon, known for its reliability in extreme conditions. But is he capable of firing? underwater? This question arises not only among military specialists, but also among hunters, divers and simply curious enthusiasts. There are many myths circulating on the Internet: from statements that AK-47 “it shoots like it’s in the air”, to stories about “complete mechanical failure” after the first shot.

In fact, the answer lies at the junction ballistics, hydrodynamics and design features of the machine. In this article we will look at:

  • 🔬 Physical principles of shooting in an aquatic environment
  • 🛠️ How gunpowder and bullets behave when in contact with water
  • 🎯 Real tests of AK-47 and other types of weapons under water
  • ⚠️ Consequences for machine gun mechanisms after “underwater shooting”

Spoiler: the result depends on the depth, type of ammunition and even water temperature. And now - to the details!

The physics of the shot: why water changes everything

In the air, the bullet accelerates due to the combustion of gunpowder in the cartridge, which creates high pressure in the barrel. But water incompressible medium (as opposed to air), and this radically changes the process.

When fired underwater, three key effects occur:

  1. Hydraulic resistance: Water is 800 times denser than air, so the bullet slows down almost instantly. Even at a distance of 1 meter, its speed drops by 10–15 times.
  2. Cavitation bubble: when the bullet moves, a rarefaction zone is formed, which collapses with enormous force, damaging the bullet itself and the barrel.
  3. Case deformation: water pressure on the cartridge case can lead to its rupture while still in the chamber, which is dangerous for the shooter.

Interesting fact: in the 1970s, the USSR experimented with special underwater cartridges (for example, 5.66x39 mm MPS for APS). They had an elongated bullet and a sealed casing, but even these were only effective at a depth of up to 5 meters.

📊Have you ever tried shooting underwater (even with an air gun)?
Yes, from pneumatics
Yes, from a firearm
No, but I want to try
No and I don't plan to

AK-47 design: what happens to the mechanism when submerged

The Kalashnikov assault rifle is not intended for underwater shooting, but it gas engine and the bolt group can theoretically work in water - if the cartridge ignites. However, there are critical issues here:

  • 💦 Corrosion: Even after one shot underwater, the untreated steel of the barrel and gas piston will begin to rust within hours.
  • 🔥 Incomplete combustion of gunpowder: The water cools the case, causing the pressure in the barrel to drop and the bullet to jam.
  • 🔄 Automation failure: the gas piston does not have time to roll back due to water resistance, and the machine stops recharging.

In 2010 the channel MythBusters conducted a test with an AK-47 underwater. Result: the first shot fired, but the bullet only traveled 1.5 meters, and the mechanism fired only once. After removal, the machine had to be completely disassembled and cleaned of rust.

What happens if you shoot from an AK-47 at a depth of 10 meters?

At such a depth, water pressure (~2 atmospheres) extinguishes the flame from the primer while still in the chamber. The probability of a shot being fired is close to zero, but even if the cartridge fires, the cartridge case will rupture, and the barrel may burst from water hammer.

Experiments and Real Cases: What the Data Says

There are several documented cases of firing an AK-47 underwater - usually in emergency situations (for example, when equipment is flooded). Here is a summary table of the results:

Experimental conditions Depth (m) Shot result Implications for weapons
Fresh water, 20°C 0,5 The shot was fired, the bullet flew ~1 m The shutter jammed after the 1st shot
Sea water, 15°C 1 Shot with case detonation Crack in the barrel, corrosion in 12 hours
Pool, 7.62×39 cartridges (reinforced charge) 0,3 3 shots in a row, bullets - up to 1.5 m Gas tube breaks after 3rd shot
River, cartridges with waterproof primer 0,2 1 shot, bullet deformed Difficulty removing the cartridge case

Important: in salt water, corrosion develops in 5–7 times fasterthan in fresh. If you have to shoot underwater, wash the mechanism immediately WD-40 solution and lubricate all parts.

💡

For emergency situations (for example, shooting from flooded equipment), use cartridges with sealed capsule (for example, 7.62x39 mm with varnished sleeve). They increase the chances of a shot, but do not guarantee the operation of the automation.

What happens to a bullet: ballistics underwater

In the air, a 7.62 mm caliber bullet flies at a speed of ~715 m/s, maintaining destructive power at a distance of up to 1–1.5 km. In water, its behavior changes radically:

  • 🌊 Braking: after 0.5 meters the speed drops to 50–70 m/s (like a crossbow bolt).
  • 🌀 Cavatation: The bullet creates bubbles of steam that collapse, damaging its casing.
  • 🎯 Trajectory: due to the density of water, the bullet begins to “yaw” and deviate from course after only 30 cm.

Experiments show that even at minimal depth AK-47 bullet loses penetrating power after 1–1.5 meters. For comparison: underwater pistol SPP-1 (caliber 4.5 mm) is effective up to 5 meters, but its bullet has a special shape and material.

💡

Underwater, the AK-47 turns into a “disposable” weapon: even if a shot is fired, reloading is unlikely, and the bullet does not penetrate even a 2-mm steel sheet at a distance of 1 meter.

Consequences for the machine: what breaks first

If you do risk shooting an AK-47 underwater, be prepared for the following breakdowns:

⚠️ Attention: after an underwater shot you can't shoot in the air right away! Water remains in the barrel, which can cause water hammer and trunk rupture.
  • 🔧 Gas tube: clogged with corrosion products and powder residues.
  • 🔄 Bolt carrier: rusts and loses mobility.
  • 🎯 Trunk: internal channels are corroded by salt (in sea water), narrowing the lumen.
  • 🔥 Trigger mechanism: Springs lose elasticity due to oxidation.

According to weapons repair shops, restoring an AK after underwater shooting costs 30–50% of the cost of a new machine. Most often required:

  1. Replacement of the barrel (due to corrosion and microcracks).
  2. Cleaning the gas system with ultrasound.
  3. Complete disassembly and lubrication of all parts.

Alternatives: Which Weapons Really Work Underwater

If you need a weapon for spearfishing or self-defense, the AK-47 is the worst choice. Instead use:

Model Caliber Effective distance underwater Features
SPP-1 (Russia) 4.5 mm up to 5 m Needle bullet, 4 rounds per magazine
ASM-DT (Germany) 4.5 mm up to 7 m Underwater shotgun, shoots harpoons
PSS "Vul" (Russia) 7.62×42 mm up to 3 m (in the air - 100 m) Hybrid gun for water and sushi

These models have:

  • 🔫 Sealed cartridges with waterproof capsule.
  • 🌊 Extended bullets for stabilization in water.
  • 🛡️ Anti-corrosion coating barrel and mechanisms.
Is it possible to shoot an AK-47 in the rain or in a puddle?

Yes, the AK-47 is designed to operate in high humidity conditions. However direct water ingress into the barrel (for example, when shooting from a puddle) can lead to water hammer. In this case:

  1. Turn the machine barrel upside down and shake to remove water.
  2. Dry it unassembled for at least 24 hours.
  3. Lubricate the mechanism before the next shooting.
What happens if a cartridge explodes in the chamber underwater?

When a cartridge case detonates in water, the pressure is directed evenly in all directions, so the risk of barrel rupture is lower than in air. However:

  • 💥 Shock wave may damage the bolt group.
  • 🔥 Shell fragments will remain in the chamber, blocking the next reload.
  • 🩹 For the shooter This can lead to hand burns from hot gases.
Are there any AK-47 cartridges adapted for underwater shooting?

No, such cartridges are not mass-produced. In the 1980s, the USSR tested experimental 7.62 mm cartridges with a sealed primer, but they did not go into production due to:

  • ⚠️ Low reliability (frequent misfires).
  • 🎯 Unstable bullet trajectory.
  • 💰 High cost (10 times more expensive than standard ones).

Today, such cartridges are used only in special underwater pistols (for example, SPP-1).

Can an AK-47 be modified to fire underwater?

Theoretically, yes, but this will require:

  1. Settings shortened barrel (to reduce water resistance).
  2. Substitutions gas system on a spring one (as in underwater pistols).
  3. Uses special cartridges with an extended bullet.

However, such a modification illegal in most countries (including Russia), as it changes the ballistic characteristics of the weapon.

What is the maximum pressure a 7.62x39 case can withstand underwater?

The standard brass sleeve is rated for pressures up to 3000–3500 atmospheres (in the air). In water this value drops to 500–800 atmospheres due to:

  • 🌡️ Cooling the sleeve (water removes heat, reducing the strength of the metal).
  • 💧 Hydraulic pressure (at a depth of 10 m it is already ~2 atm).

If the limit is exceeded, the sleeve ruptures, which can lead to shutter damage or injury to the shooter.