The Science behind Underwater Bullet

As we talked in the previous article (, the ordinary bullets have limited ability when it is used in water. Its strength will be reduced due to the density of water that is much greater than air, so the bullets speed released from the gun becomes slowly.  The speed of the bullet moving out of the rifle is actually affected by several factors:

Underwater Ammunition (GP Bullet)
Underwater Ammunition (GP Bullet)
  • Gyroscopic inertia or bullet stability. The barrel gun has a spiral groove that makes the bullets spin very fast when it comes out. When the bullet continues to spin, the straightforward movement will be disturbed and eventually it turned.
  • Space density. Air or water will provide frictional force to the bullet so its energy kinetic will decrease. Water has a density 800 times greater than air, so the ordinary bullet was only able to come out a few centimeters from the shotgun and become falling down.
  • Gravity. For very short distance, bullet can do a straight line but it follows sight downward curve for a long distance because gravity force will pull it down to the ground.
Supercavitation effect

Space density is a factor that greatly influences the speed of the bullet in case of underwater uses. So, special design is needed to overcome these problems. Duretek Co., Ltd has developed a promising new bullet design for this situation by name GP Bullets. Type of the Multi Environment Ammunition (MEA) which will work best for both open air and underwater with same power and precision. It uses the supercavitation principles which it can create a bubbling gas inside the water. It is large enough to cover the whole edge of the bullet passes through the liquid phase.  This will reduce the frictional force arising from the touch of a bullet with the water particles so the bullet can reach the underwater target with very high speed.

33 comparison
The comparison of the center of gravity location

Furthermore, to reduce the gravity force and increase the bullet stability we adjust the center gravity of bullet close to its center pressure. By using high specific gravity material in the front and material with relatively low specific gravity on the rear. It makes better stability in flight, follow the straight movement, and increase the speed of the bullet.




These GP bullets have various type from 5.56 mm, 7.62 mm, 9 mm and 12.7 mm size are available. It can be applied to various warheads. Also, as multi-environment ammunition bullets certainly will work both open air and the underwater situation with the same power and precision. GP bullet will have more power in the air than an ordinary bullet with high destructive power. If you interested with GP bullets, please contact

  • Related article : True multi-environment ammunition