There are few firearms out there than can do anything else but kill. But, as you might have noticed in the last few decades, military forces around the world are constantly heading towards developing non-lethal weapons that wound or disable the individual instead of killing him. The US Army is no exception to this rule and has started funding a project that could end in the creation of the next generation of bullets that could have variable speeds.

What is really surprising about this is that the developer is a toy design studio known as Lund and Company Invention, specialized in creating toy rockets fueled with liquid hydrogen that vary their impulse at launch by regulating the fuel-air ratio in the combustion chamber. The development of the variable speed bullet could see weapon manufacturers design non-lethal weaponry that can also kill if necessary, resolving one of the last problems regarding the implementation of non-lethal weapons in the US Army.

VWS, or the Variable Velocity Weapon system, works by varying the muzzle velocity of the weapon, which in turn affects the speed at which the bullet travels. The primer and the case of classic projectiles become obsolete in VWS, since they are incorporated in the weapon itself. The case is replaced with a combustion chamber behind the bullet, while the primer is swapped with a liquid explosive mix. Just like with the toy rockets produced by the company, by varying the amount of fuel and oxidant in the combustion chamber, one can obtain different bullet velocities.

"Projectile velocity varies from non-lethal at 10 meters, to lethal at 100 meters or more, as desired," says the company's CEO, Bruce Lund. He also said that the weapons would become much lighter and could generate less heat than current ones without losing properties characteristic to long-range sniping.

The downside is that as in the case of non-lethal shotguns used by the Police, which shoot 'beanbags', the weapon would require two types of ammunitions depending on its applications. The same technology could eventually be scaled up to even bigger models such as the Howitzer, for example.

"In a high-stress, high-personal-risk zone, there will be a real temptation for soldiers to turn the tunable lethality switch up to 'kill' mode so that all doubt is removed," warns Steve Wright, a security expert from Leeds Metropolitan University.

According to Lund and Company Invention a prototype of the new VWS technology should be available by the end of the year and could enter mass production in as little as 18 months.