According to what reported by the specialized site Defense One, the US Special Operations Command is testing projectiles that can be fired underwater.
The difference between underwater and regular bullets is remarkable: the latter slow down significantly underwater. They do not pose a serious threat, because water is eight times denser than air and greatly weakens them.
If the bad guys in action films use "simple" harpoons in certain "aquatic" situations, there must be a reason...
Through every element
The goal of the underwater projectile project is to enable divers and soldiers trained in marine and underwater environments to attack with new generation weapons boats from beneath the surface. Another opportunity offered by this type of weapon is being able to hit submerged submarines even from a helicopter.
Tungsten tip
According to Business Insider the underwater projectiles were funded and tested directly by the Secretary of Defense's Office of Counterterrorism Technical Support.
Military contractor DSG Technologies created underwater projectiles by modifying regular ones to add a small tungsten-coated tip. Special underwater pistols, and more generally new underwater weapons complete the picture.
This measure allowed the bullets to create a small air bubble in front of them. It is a typical phenomenon called "supercavitation": the bubble has the effect of reducing the resistance of the water, a bit like what happens with torpedoes.
The CavX Underwater Bullet Test
DSG Technologies showed its CavX Multi Environment ammunition in a shooting range in Fayetteville, North Carolina. In the test, the bullets were fired with a Colt AR-15 through 13 blocks of 40cm thick ballistic jelly.
Here is a video that illustrates the phases of the field experimentation of underwater projectiles:
A .50 caliber CavX bullet can travel 60 meters underwater without encountering obstacles of any kind. And no, you wouldn't have time to dodge it.
