In response to the upsurge in gun violence, politicians are proposing restrictions on the number of bullets that handgun and rifle magazines can hold. And just as they do, new printing technology blows holes right through that debate. The 3-D printing gunsmiths at Defense Distributed are about to release blueprints for an upgraded magazine that won't degrade even after you fire hundreds of rounds.

Meet the "Cuomo." It's a new printed magazine for your AR-15 rifle, soon to be available for download, and it holds 30 bullets. Upgrading an earlier design that didn't hold up particularly well after extended use, it's an unsubtle rejoinder to New York Governor Andrew Cuomo, who recently signed a magazine-restriction law limiting mags to seven rounds. Defense Distributed is basically saying that if you're not going to be allowed to buy larger magazines in the near future, you can print them yourself – if, that is, 3-D printed weapons don't fall into legislators' own crosshairs.

In recent tests at a gun range near Austin, Texas, Defense Distributed fired a total of 342 rounds using the magazine with no issues, according to the group's founder, Cody Wilson. The group fired 227 of those rounds using full automatic fire, while swapping out the barrels on the rifle to keep them cool. The group also uploaded a promotional video, seen above, demonstrating a portion of the test.

"We had been making revisions to the file demonstrated in January, but it was at its core not a good file, so total redesign from scratch," Wilson e-mails Danger Room from London, where he's attending a conference for the Bitcoin digital currency. "The mag won't fail in limited engagements," he added.

The problem with the first magazine, according to Wilson, were "slightly uneven dimensions," including a magazine catch slot – where the magazine locks into the rifle – that caused repeated jams. The group also reverse-engineered the device, but found the magazine's spring-loaded follower – which feeds bullets upwards as the rifle cycles through them – and its base plate had "tiny impractical parts." It wasn't really workable, so Wilson redesigned the shape and added a new follower. "Basically the mag is a total redesign," he says.

Defense Distributed emerged at the forefront of 3-D printed weapons last September after a printer leased by the group had its contract voided – and printer seized – by 3-D printer firm Stratasys. This kind of printing, or "additive manufacturing," involves using layers of thermoplastics and computer-aided design files to construct everyday objects. The group's move into printing magazines is a more recent shift. Printable magazine blueprints have been available online for more than a year, but most designs are crude and impractical.

Defense Distributed also plans to produce a 40-round magazine for AK-47-type rifles. But some legislators urge restrictions on 3-D printed weapons, so technology doesn't render new gun laws obsolete. Last month, Rep. Steve Israel of New York called for 3-D printed magazines to be banned. More broadly, magazines of more than 10 rounds were restricted until the 1994 Assault Weapons Ban expired in 2004. New York's recent law banning magazines greater than seven rounds would also make Wilson's magazine illegal – but difficult to control if getting one is as simple as printing it off the internet.

Hosting may not be a problem. The group had early blueprints pulled from the Thingiverse printable file database last year by its owner, MakerBot industries, with another purge of gun parts to follow after the tragic mass shooting at an elementary school in Newtown, Connecticut.

But Defense Distributed has since set up its own online clearinghouse Defcad. "Since this project is really about open source software, we know we need to release strong, usable templates," Wilson writes. "If we really want to encourage adoption and experimentation, we've got to start releasing workable STLs and reliable CAD files." The upgraded printable magazine should be online at Defcad in the next few days.