3.) He printed a AR-15 lower receiver, which is the part, under US law, considered a "firearm". The high pressure components (barrel, bolt) are all made from conventional manufacturing processes, using steel.
Lowers are typically made out of aluminum, but they don't really experience any great stresses, so it's perfectly possible to make them out of plastic. (There's a number of commercial lowers made out of fiberglass: http://www.mdshooters.com/showthread.php?t=65134 (I'd link directly to the manufacturer's site, but it seems they're better at making guns than they are at securing web servers)) As he notes, people have even carved them from wood.
Does HN have any mods?
2.) Have blue has a blog, he's written two posts about this: http://haveblue.org/?p=1041 http://haveblue.org/?p=1321 It appears to be down right now, though. Cache links: https://webcache.googleusercontent.com/search?q=cache:DlBe32... https://webcache.googleusercontent.com/search?q=cache:Z_5bOF...
3.) He printed a AR-15 lower receiver, which is the part, under US law, considered a "firearm". The high pressure components (barrel, bolt) are all made from conventional manufacturing processes, using steel.
Lowers are typically made out of aluminum, but they don't really experience any great stresses, so it's perfectly possible to make them out of plastic. (There's a number of commercial lowers made out of fiberglass: http://www.mdshooters.com/showthread.php?t=65134 (I'd link directly to the manufacturer's site, but it seems they're better at making guns than they are at securing web servers)) As he notes, people have even carved them from wood.