The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) this week released videos of tests of plastic guns made with 3D printers that show some exploding on the first shot. The explosions could injure users, the testing found.

The ATF has been testing guns made with 3D printers using two commonly used thermoplastic materials over the past year to determine how safe the weapons are.

ATF firearms experts test a 3D printed gun created by polymers from VisiJet. The gun continually exploded on the first shot.

Guns made using one of the two thermoplastics tested, a polymer from VisiJet, never lasted more than one shot before exploding. The other material, acrylonitrile butadiene styrene (ABS), could produce a gun that fired 8 times without incident.

The agents stopped shooting after 8 bullets, an ATF spokesperson said.

"It depends on the material as well as the quality of the printer. Those variables both go into it," the spokesperson said.

The spokesperson wouldn't identify 3D printers used or which computer-assisted drawing (CAD) files were downloaded to create the weapons.

A 3D printed gun using ABS was able to fire 8 times without incident.

The firearm tested, however, looked like The Liberator, the world's first 3D printed gun, which was created by Cody Wilson and his company Defense Distributed. Cody has said he was able to successfully fire the weapon after it was printed using a second-hand industrial Stratasys Dimension SST 3D printer. The machine, about the size of a refrigerator, was purchased for about $8,000 from eBay.

3D printers also come in hobbyist desktop versions that produce lower quality objects, but also cost from about $500 to $3,000.

The ATF also released a list of answers to commonly asked questions about 3D printed firearms, such as whether or not they're legal to make.

A law passed in 1988 required any gun manufactured to have enough metal to be detected in metal detectors. However, that law is due to expire next month.

Lucas Mearian covers storage, disaster recovery and business continuity, financial services infrastructure and health care IT for Computerworld. Follow Lucas on Twitter at @lucasmearian, or subscribe to Lucas's RSS feed . His email address is lmearian@computerworld.com.