In the news is Have Blue, a hobbyist from the AR-15 forum who has become one of the first people to construct an AR-15 class assault rifle using a 3D printer. Have Blue used 3D CAD files from CNCGunsmith.com to print the gun's lower receiver, the part that in a legal sense actually constitutes a firearm. After making some minor changes to the design, he fed about $30 worth of standard ABS plastic into his fairly old school Stratasys 3D printer and combined the body with off-the-shelf, metal AR-15 parts to complete the gun. Afterwards he loaded the gun with relatively low-powered .22 caliber pistol rounds and after firing 200 rounds he posted online that it runs great, without visible signs of wear and tear.
The lower receiver was created using a fairly old school Stratasys 3D printer, using a normal plastic resin. HaveBlue estimates that it cost around $30 of resin to create the lower receiver, but “Makerbots and the other low cost printers exploding onto the market would bring the cost down to perhaps $10.” Commercial, off-the-shelf assault rifle lower receivers are a lot more expensive. If you want to print your own AR-15 lower receiver, HaveBlue has uploaded the schematic to Thingiverse.Much more information can be read at Have Blue's website.
HaveBlue tried to use the same lower receiver to make a full-blown .223 AR-15/M16 rifle, but it didn’t work. Funnily enough, he thinks the off-the-shelf parts are causing issues, rather than the 3D-printed part.
Source: ExtremeTech