A bit more grist for the mill on gun availability

Downloading a gun's design plans to your computer, building it on a three-dimensional printer and firing it minutes later. No background checks, no questions asked.

Sound far-fetched? It's not. And that is disquieting for gun control advocates.

Rep. Steven Israel, D-NY, said the prospect of such guns becoming reality is reason enough for the renewal of the Undetectable Firearms Act, which makes illegal the building of guns that can't be detected by X-ray or metallic scanners. That law expires at the end of 2013.

At least one group, called Defense Distributed, is claiming to have created downloadable weapon parts that can be built using the increasingly popular new-generation of printer that utilizes plastics and other materials to create 3-D objects with moving parts. University of Texas law student Cody Wilson, the 24-year-old "Wiki Weapons" project leader, says the group last month test fired a semiautomatic AR-15 rifle - one of the weapon types used in the Connecticut elementary school massacre - which was built with some key parts created on a 3-D printer. The gun was fired six times before it broke.

Though no independent observer was there to verify the test, a short video clip showing the gun firing and breaking was posted to YouTube. Federal firearms regulators said they are aware of the technology's gun-making potential, but do not believe an entire weapon has yet been made.