According to a report by The Washington Post on February 19, people in the United States can now download blueprints from the Internet and use 3D printers to easily print gun parts and ammunition magazines. The incident caused social panic and posed a greater challenge to the Obama administration's gun control efforts.

Travis Lerol, a 30-year-old software engineer, demonstrated to reporters at his home that he could easily print plastic rifle parts and ammunition magazines using only a 3D printer. Lerol said he did not want to print anything that violated the law, but was concerned about how it would affect the government's new gun control laws. "It's hard to monitor what people do at home," he said.

It is not known how many people use 3D printers to get their hands on gun parts and ammunition magazines, but the designs are thought to have been downloaded hundreds of thousands of times. A "Defense Branch" organization set up by American college students has successfully printed gun parts from 3D printers and uploaded the design blueprints to the Internet for people to download and use.

Since February last year, Cody Wilson, a law student at the University of Texas in the United States, and his friends set up an organization called "Defense Branch", and rented or bought a number of 3D printers through fundraising, and successfully printed gun parts such as gun stocks, gun handles and triggers after modification. And even printed a plastic 30-round AR-15 rifle magazine, one of the most popular rifles in the United States.

Wilson doesn't consider himself a gun or machine enthusiast, but says he did it to challenge government gun control. He wants "anyone to own it, anyone to print it, anyone to use it." The group was unable to print the chamber and barrel because it was too difficult, but the techniques were enough to make many people nervous.

Although the printed guns are still knockoffs at this stage, technology experts and gun advocates agree that being able to print firearms and ammunition magazines is enough to pose a challenge to President Obama and gun control lawmakers. Members of Congress and gun advocates are shocked by the ease with which 3D printers can create gun parts.

"I believe 3D printers will have a more positive impact on the world, but I am concerned that the resulting gun parts and ammunition cartridges could easily be carried on airplanes and pose a safety risk," said Steve Izriel, a US representative from the Democratic Party. Izriel said airport scanners would not be able to detect the 3D-printed gun parts and magazines, and he is concerned about the threat to national security. Izriel plans to introduce laws to tighten controls.

However, Holder Lipson, a 3D printing expert at Cornell University in the United States, said that US law has long allowed individuals to make weapons, but it is difficult for ordinary people to do so because of technical reasons. He said that in addition to the need for a 3D printer, people have to download the design from the Internet, print it and then assemble it. Making a gun requires mechanical knowledge and a variety of parts, which takes a lot of time.

According to The Economist, such fears are overblown, and homemade guns for personal use are neither illegal nor new. An official with the US Bureau of Alcohol, Tobacco and Firearms said that she had seen all kinds of homemade guns, including pens, books, belts and sticks. "Anything you can call a name, people can turn it into a firearm."

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