A federal judge has ruled Cody Wilson could not post designs for 3D-printed guns on his website. So Wilson took advantage of a loophole -- he is selling them directly to customers.

"It's a matter of principle," Wilson said Wednesday on "CBS This Morning."

"I know it's absurd to some degree to fight for your principles in a culture like this, but I think it's a worthy demonstration, and of course, I could always demonstrate, like today, that I can always sell these files. And I'll continue to do so," said Wilson, who distributes the files through his company, Defense Distributed.

Customers can name their own price.

Attorneys general in 19 states and the District of Columbia claimed victory when Wilson was blocked from posting the blueprints on his website. But the judge's ruling on Monday offered a workaround: "Files cannot be uploaded to the internet, but they can be emailed, mailed, securely transmitted, or otherwise published within the United States."

Asked about selling AR-15 blueprints in the seven states where they are illegal, Wilson said there's no need to separate files because "in different configurations" it's "legal to make in every state in this country -- even today."

"Even if I couldn't make an AR-15 in California, which I can, I can still have the file for an AR-15. This is a separate question of law and a separate question of fact," Wilson said.

In light of Sunday's shooting at a video game tournament in Jacksonville, Florida, "CBS This Morning" asked whether Wilson was concerned that a mentally ill person could get access to the blueprints. According to court records, the gunman who killed two people and wounded 10 others before killing himself had a history of mental illness and anger issues.

"Sure, I mean there's always a possibility that people with a history of mental illness can get access to information and somehow do something bad with it. But we live in a nation of laws and you should prosecute crimes after the fact," Wilson said. "You know, this gentleman who shot up this game tournament in Florida legally bought that firearm. The law is there to prevent bad things from happening but to do no more than that."

In 2013, Wilson became the first person to fire a bullet successfully from a home-printed 3D gun. He said he tracks who he sells his blueprints to, and he has sold "many hundreds" and "probably in the thousands at this point."

"I'm required to do all kinds of screening and stuff. I can only ship to U.S. persons, U.S. citizens. There's all kinds of arms-export control stuff that we have to comply with. But of course I've had many years to become comfortable and become compliant with these laws," Wilson said.