Diving underwater to avoid folks shooting at you …

… actually works pretty well …

The team then switched to a swimming pool to continue the experiments – and to make the test more realistic, switched from shooting straight down to an angle of twenty to thirty degrees off the vertical, approximating a shooter standing on the edge of the water and shooting out into it.

The first candidate for this test was the Civil War rifle. At a range of 15 feet, the ballistics gel was completely unharmed; likewise at five feet. Only when the range was reduced to three feet did the bullet finally penetrate the gel, suggesting that diving under water was probably a pretty effective way of dodging slugs during the Civil War.

The experimenters moved on to the hunting rifle, which was loaded with a full-metal jacket .223 round that emerged at roughly 2,500 feet per second. At ten feet, the bullet disintegrated and the gel was untouched. At three feet, the bullet again broke up, with its tip coming to rest on the gel – not nearly enough power to damage flesh.

A bullet from the M1 Garand, with a muzzle speed of 2,800 ft/sec, also disintegrated at the ten-foot range. At two feet, the slug penetrated about four inches into the gel, suggesting a non-fatal wound. The armor-piercing .50 caliber round didn’t do any better – it, too, came apart at distances greater than five feet and lost most of its punch by three feet.

… unless you’re going up against special forces units with specially designed underwater firearms.

The engineers at the Central Scientific Research Institute for Precision Machinery Construction in Moscow correctly perceived the problem with shooting into water and in response developed the SPP-1 (Spetsialnyj Podvodnyj Pistolet, or “Special Underwater Pistol”) for use by Russian Navy frogmen. The SPP-1 is a manually operated four-barrel handgun that breaks open along the top and loads in a fashion similar to a double-barrel or over-and-under shotgun. The ammunition is designed to work underwater,
using long bottlenecked rimmed casings plus bullets made from mild rather than hardened steel and designed to be stable underwater. The barrel isn’t rifled. According to the specs for the pistol, when fired at a depth of five meters – over sixteen feet – it’s lethal up to seventeen meters, or over fifty-five feet.

(via GeekPress)