Nice Clear Water.
The Daily Mail Online who ran this story typically describes the firearm only as an "Assault Rifle".
Andreas can certainly claim to have the courage of his conviction - it takes some cojones to stand there and pull that trigger eh - there are no leakage stains shown in the water around his shorts.
A great shooting Video.
Victory Retrieve - One Bullet.
The basic physics is that most guns may be fired under water provided that the barrel is completely filled with water and that the firing pin has enough energy to strike the primer properly. - But the bullet will rapidly loose velocity and fall because water is some 800 times denser (thicker) than air.
- Just as well that he didn't use one of these eh:
Tula Arms Plant Underwater Pistol uses Four Round 'Moon Clips'
- Flechettes or Darts have a 17 metre Effective Range at Shallow Depths
Well done that man - but I bet that he tested that gun and ammo first eh,