New York Sen. Charles Schumer said the ability to make an untraceable and undetectable gun with a 3-D printer is "stomach-churning."
He said the guns are capable of firing real bullets and pass unnoticed through metal detectors.
Schumer said the technology means anyone "can open a gun factory in their garage."
He said the company, Defense Distributed, last week announced it had successfully made the plastic gun using a 3-D printer. The senator said the company plans to post blueprints for the weapon online this week.
A spokesman for the company couldn't be reached for comment.
Rep. Steve Israel (D-Huntington) recently introduced an Undetectable Firearms Act that would make it illegal to "manufacture, own, transport, buy, or sell any firearm, receiver or magazine that is homemade and not detectable by metal detector and/or does not present an accurate image when put through an X-ray machine."
The reauthorization would extend the the bill for 10 years. The existing ban on plastic guns expires this year, Israel said.