There are several designs of weapons printed in 3D now available for free on the web.
These weapons are capable of killing and accurately imitating the weapons of real life.
As they are made of plastic and not metal, they can be taken through metal detectors without being picked up.
In 2013, Mail on Sunday exposed the international security risk posed by a gun that can be easily manufactured with new 3D printers.
They built a weapon, which is capable of shooting a live round, from maps available on the Internet, and then smuggled it into a full Eurostar train.
Defenders of gun control argue that 3D-printed pistols could go unnoticed by metal detectors. However, to be legal, they must contain detectable metal parts
Two reporters went completely un-interrogated through strict airport-style security measures to take the gun to a service from London to Paris in the rush hour of the weekend, along with hundreds of unsuspecting travelers.
The pistol, capable of firing a deadly bullet of 0.38 caliber, was produced in less than 36 hours using a revolutionary £ 1,700 machine to "print" its components.
And since all the pieces are made of plastic, they did not activate the metal detectors that all Eurocopa passengers must pass through.
To be considered legal, weapons must contain detectable metal parts.