A lot of gun people are currently pooh-poohing 3D gun manufacturing as low end bullshit for techie geeks who don't know jack about guns. A lot of that is based on the fact that all anybody ever talks about are polymer or plastic guns.
The following article should be a wake up call to these types as well as the people who make and enforce the firearms laws here in the U.S.
Despite everybody's best efforts, technology is marching on whether society, the government, or entrenched business interests like it or not.
Methinks the BATFE will be pulling the hair out of their collective head as they effectively become increasingly irrelevant over the next 5 to 10 years judging by the leaps and bounds that are appearing in the technological developments of the manufacturing sector.
Now mind you, make sure you read the whole article. This gun was not made on some cheap desktop 3D printer. But as time goes on, the cost and size of these things will also get smaller and smaller.