This is not 'printing a gun', this is printing two passive parts that you could just as well have whittled from wood or cast or put together in a hundred different ways. The 'load bearing parts' of a gun are the barrel, the breech and the trigger mechanism. For the sake of the argument let's pretend that the title is right and that you can 'print a gun'.<p>You could always make a gun, all you needed was a lathe, some tooling, a hacksaw a file, some steel stock and a bunch of patience.<p>Printing a gun is just another way to get to the goal, possibly an easier one but one with its own unique challenges.<p><a href="http://en.wikipedia.org/wiki/Improvised_firearm" rel="nofollow">http://en.wikipedia.org/wiki/Improvised_firearm</a><p>The differentiating factor for a gun from printed ABS is not that you've made it at home, but that it is very hard to detect the gun itself (you'd have a hard time not using metal at all, especially for the parts mentioned above and then there is the ammo).<p>You can bet that if you get caught with one trying to board an airplane that there will be very serious repercussions, you won't be able to say you left it in your carry-on luggage by accident. Well, you can say that but good luck to get anybody to believe you.<p>So, printing a gun is not the same as buying a gun, it is the same as making a fire-arm at home through conventional means.<p>On another note, the design of a working firearm, especially from unproven materials, is not something you muck around with unless you know your materials science. A gun that explodes when fired could have some pretty nasty effects on you and bystanders.