Undated handout photo made available by Greater Manchester Police in northern England Friday Oct. 25, 2013 of a component made with a 3D printer.
WASHINGTON - When a decades-old law banning undetectable firearms expires less than a month from now, federal agents say a plastic weapon created on a 3-D printer could emerge as a national security threat.
The homemade plastic gun, known as the "Liberator .380" and made with a computer blueprint, a 3-D printer and plastic resin, could pass through security checkpoints at courthouses, schools, sporting events and other buildings without setting off metal detectors.
The guns use only the smallest bits of metal for ammunition and a firing pin the size of a roofing nail.
The Undetectable Firearms Act, passed in 1988 and renewed in 1998 and 2003, expires at midnight Dec. 9. The law, which envisioned gun manufacturers using more plastic as technologies improved, requires guns to have enough steel to set off a metal detector.
"It's not theoretical anymore," says Earl Griffith, chief of firearms technology branch at the federal Bureau of Alcohol, Tobacco, Firearms and Explosives. "This law made sense in 1988. It was forward-thinking in 1988."
Sens. Bill Nelson, D-Fla., and Charles Schumer, D-N.Y., and Rep. Steve Israel, D-NY, have proposed an updated version of the bill that would ban the design, manufacture, sale, import, export and possession of the 3-D plastic guns. The new bill requires a gun's receiver, slide and barrel to be made from metal.
"Back then, in 1988, the notion of a 3-D plastic gun was science fiction," Israel said. "Now, a month away, it is reality."
Lawmakers could extend the existing "invisible weapons ban" or close the old law's loophole that allows a gun owner to make a plastic gun legal simply by attaching metal to it.
"The expiration of this law, combined with advances in 3-D printing make what was once a hypothetical threat into a terrifying reality," Schumer said in a statement. "We are actively exploring all options to pass legislation that will eliminate the threat of completely undetectable weapons."
The National Rifle Association did not return a call for comment.
The gun, as designed by Cody Wilson of Defense Distributed of Texas in 2012 and then posted on the Internet, has been downloaded more than 100,000 times before federal officials blocked the site in May, the senators said in a letter to their colleagues.
Wilson's design includes a block of metal that is inserted into the gun, making it legal under the current act. But the gun can be dismantled into several parts and the metal removed, making it illegal, but also harder to detect, even at security points with x-ray technology, Griffith said.
Agents from ATF created and tested several of the guns using the blueprints and different grades of plastic resin. It took a high-end 3-D printers 10 to 18 hours to print the parts and cost $80 to $170 in materials, Griffith said. The gun made from lower grade plastic shattered into a dozen pieces after shooting one bullet. A second gun, made from a higher grade resin, fired eight bullets and remained intact, Griffith said.
A bullet fired from the plastic gun did nearly the same amount of damage as a bullet fired by a metal gun, penetrating nearly 11 inches into material that resembles the soft tissue of a person, he said.
"The fact that anyone with the right equipment can make a fully-functioning weapon from their own home with the click of a mouse is a truly frightening concept," Nelson said in a statement "Weapons like this pose a serious threat to our national security and we need to do everything we can to keep them off our streets"
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