Causing large wounds like craters, how do supersonic bullets threaten people?

Supersonic bullets leave wounds as large as craters, but do not penetrate skin and flesh as solids like traditional shots.

That's the result of a military animal study in China.

Researchers from a military medical center in the southwestern metropolis of Chongqing city (China) fired high-speed 5mm steel bullets at sedated young boars to assess the potential effects of the disease. Hypersonic weapon with human body.

Hypersonic weapons are an intense area of ​​military research, with Russian defense contractor Lobaev Arms saying in 2019 that it was developing a hypersonic rifle that could accelerate bullets to near Mach 6 (2058 meters/second).

The projectiles in the Chongqing experiment were fired into the thighs of each pig and reached speeds of up to 4,000 meters per second, more than 11 times the speed of sound.

According to a paper published August 22 by researchers in Acta Armamentarii, the official journal run by the China Materials Association, the shots didn't kill the pigs immediately, but the shockwaves. from the bullets caused serious injuries all over the body.

'Large-scale lesions with multiple organs can be seen at the time of injury, mainly fractures and bleeding in the intestines, bladder, lungs and brain,' according to the research team led by Wang Jianmin. at the Weapons Biological Effects Evaluation Department of the Army Special Forces Medical Center in Chongqing. The pigs died within 6 hours of testing.

Autopsy results showed that the bullet penetrated the thigh at a speed of 1,000 to 3,000 meters per second.

'But at 4,000 meters per second, the bullet did not penetrate the hindquarters and a large wound cavity was formed at the point of impact,' said Wang Jianmin and colleagues.

Most guns have a bullet velocity (the speed of a bullet as it exits the barrel) below 1,200 meters per second, or about three times the speed of sound. In these cases, a bullet will penetrate the skin and flesh as a solid substance, according to Wang Jianmin. But at very high velocities, the temperature of the bullet can be close to the melting point.

'The bullet appeared to ignite when it came into contact with the animal's skin, suggesting that the steel ball itself was subjected to a tremendous amount of force when it hit, melted and broke apart at high temperatures. It forms a huge wound cavity similar to a hemispherical crater (crater), accompanied by a large amount of tissue splashing,' the paper said.

Under these conditions, the bullet and the flesh turn into liquids and gases, the researchers say, so the physics of the collision should be described as fluid mechanics.

According to Chinese scientists, supersonic bullets differ from traditional bullets in that the wound has destructive power on the human body.

Researchers in Chongqing say more animal experiments will be conducted targeting 'heads, chests, abdomens and other body parts with more complex structures'.

Targets made of soap can produce some of the same effects, simulating the movement and transfer of energy of bullets in soft tissue, according to the researchers.

However, animal studies are needed to understand the lethal properties of bullets with biological targets, they say.

Hypersonic weapons are considered one of the frontiers of military science.

For example, the Lobaev Arms sniper rifle can hit a target 1km away in half a second, eliminating the need to adjust for wind, gravity and movement.

There are no open reports of China developing hypersonic weapons, but the Chinese military has funded many projects on weapons that can fire small projectiles at speeds higher than Mach 5 (1,715 meters per second). ). For example, the Chinese navy is investigating whether these hypersonic rounds could be used as part of a ship defense system to intercept enemy drones, missiles or torpedoes. are not. However, according to an explosion physicist, the development of hypersonic weapons faces many challenges.

Most existing gun powders cannot generate enough energy to propel a bullet to such high speeds, and the gun will need to be completely redesigned with super-hard materials to withstand the explosive force, according to the house. The study requested anonymity due to the sensitivity of the technology.

The researcher says that how far the bullet will travel remains uncertain if it melts and changes shape in the air.

Other issues such as mobility and noise can also affect the actual value of such a weapon in battle, he added.

China and the US are two of the countries developing pistols that can launch hypersonic projectiles over a distance of 200km using electromagnetic propulsion, but the reduction in size, wear, and energy consumption of the systems This is still a challenge.