Late last year, a group of 3-D printing gunsmiths developed a key component for an AR-15 rifle that anyone with a 3-D printer could download and make at home. The problem: It only lasted six shots before snapping apart. Now the group is back with a new and improved receiver that can fire more than 600 rounds.
Defense Distributed demonstrated the receiver ' the base of a gun that includes the trigger mechanism ' in a video posted this week to the group's blog. Its arrival comes the week Congress returned from vacation to debate a series of potential gun regulations. In the video, dozens of bullets contained in a high-capacity drum magazine are seen being fired by the printed receiver. (The magazine was shoved into the printable receiver, itself attached to traditional rifle parts.) It's also the first printable receiver to fire .223 caliber high-pressure rifle rounds without breaking. An earlier version fired low-pressure .22 caliber cartridges.
It's important to note that fully 3-D printed guns don't exist yet. So far, activist groups like Defense Distributed and individual hobbyists have produced only partially printed weapons ' usually, printed magazines.
That's still a big deal, though. With no lower receiver, printable or not, there's no gun. For legal and regulatory purposes, the lower receiver is the piece of the firearm that's considered the gun ' not the barrel, magazine, buttstock or other component. A world where the blueprints for a gun's most critical component can be freely shared online, downloaded, and then printed out, raises thorny questions about the feasibility of regulating them. Last week, one 3-D printing pioneer told Danger Room it'd be more feasible to regulate the gunpowder.
The printable components are also getting more advanced. Printable magazines have been produced that don't fail after releasing hundreds of rounds. Late last year, Defense Distributed tested a 3-D printed lower receiver for an AR-15, but it snapped apart after firing only six shots. Pushing up that failure point became the difference between having a 3-D printed gun that works and a gun that doesn't ' not to mention one that's safe to use.
The group had to take out as many angles and points of stress inside the new receiver as possible, thicken several areas to withstand pressure from vibrations, and 'let the piece act more as a spring,' developer Cody Wilson e-mails Danger Room. Angles below the buffer tower ' which helps absorb recoil ' were also curved and strengthened. The group still had to bolster the piece with some metal parts, though. A one-eighth inch compression bushing is embedded in the back.
The group also produced two receivers with two different printers. One was produced by a stereolithography (SLA) printer, which uses beams of high-powered light to cut light-sensitive liquids ' called SLA resin ' into a pre-determined shape. The other receiver was produced by a fused deposition modeling (FDM) printer, which uses heat to harden thermoplastic that's squirted out in very thin layers. The latter also 'approximates the result you'd get with an ultimaker or other DIY FDM printer. So both [are] cheap and accessible,' Wilson e-mails.
'The changes had been in note form for a while. It's just that we were directing the lion's share of our efforts on magazines for a month,' he adds. In the meantime, the group plans to get back to testing 3-D printed magazines. This weekend, the group plans to reveal a printable AK-47 magazine, which will be a first. Congress, get ready to freak out.
Tidak ada komentar:
Posting Komentar