Borepatch says it well:
Freedom is by its very nature, Open Source. Personally, I find rich irony in seeing how people who back in the day thought themselves to be True Revolutionaries are horrified when they see something truly revolutionary. I'm not sure that I'd every want to shoot one, but the idea that I could if I really needed to.
And yes this contrasts with Google's view on arms and the global distribution therein here.
Via JayG who notes what this means for the world and the antis
The ramifications of this project are staggering, and will most likely outpace legislation. Owning a 3D printer and a CAD program is hardly "constructive possession, and it's hard to see how having plans for a pistol - even with the CAD program and printer - would constitute same, even for a prohibited person. Being able to quickly, cheaply, and easily produce firearms by the thousand - tens of thousands, or maybe even hundreds - may very well be the lever that forces us to reckon with the person that misuses the tool rather than the tool itself.
This project makes real what we on the pro-rights side have been saying for decades: Any person bent on ill intent can get a firearm at any time. Those that will do harm will not be stopped by any laws made by men; at the very best they might be delayed. Putting artificial barriers to firearm ownership only hurts those that need not be regulated - the good people - and allows the evil people to thrive.
Knowing that anyone, at any time, anywhere, might have a simple gun on their person is fantastic protection from goblins - and out-of-control governments.
Also the "ironic" part if this technology is that countries and states that actually respect gun rights would find this technology to be a minor disruption. As the general citizen can already purchase and carry a firearm.
Those states where the general public cannot however....
But this shows the core idea that liberty is liberty.