Obligatory "Shit Shovel" AK-47: http://www.northeastshooters.com/vbulletin/threads/179192-DI...!

TL;DR: A man starts with a shovel (formerly used for shovelling shit) and forms an AK receiver using little more than a furnace, some hammers, a spot welder and a drill.

So yeah, the printers change very little. What they have actually done is effectively communicated the idea that guns can be made in your garage (previously that message was not getting through for some reason which I cannot for the life of me understand).