Story highlights Law requiring all guns include enough metal to be detected during screening to expire

Congress must act by next week to renew law, but wrangling continues

White House and Democrats want tougher measure than House-approved bill

Concern growing about plastic guns made through 3-D printing

The U.S. House on Tuesday approved a 10-year extension of a federal law requiring that all guns be detectable by metal screening machines.

But partisan wrangling could still mean the Undetectable Firearms Act, approved 25 years ago, will expire next Monday.

The law prohibits guns that don't contain enough metal to trigger screening machines commonly found in airports, courthouses and other secure areas accessible to the public.

It has become an issue with the advent of 3-D printers, which the Bureau of Alcohol, Tobacco, Firearms and Explosives recently said its tests showed are capable of producing lethal firearms entirely made of plastic.

JUST WATCHED First metal gun made with 3-D printer Replay More Videos ... MUST WATCH First metal gun made with 3-D printer 00:44

A one-sentence bill by Rep. Howard Coble, R-North Carolina, was approved easily by House lawmakers and sent to the Senate.

The Obama administration and congressional Democrats want any extension to also deal with potential loopholes for 3-D-printed guns, which the House bill does not do.

Currently, plastic guns made using 3-D printers comply with the law by inserting a removable metal block.

That has led to worries that plastic guns could pass through metal detectors without being flagged by simply removing the block, which isn't required for a 3-D-printed gun to operate.

Plastic components have become common in popular guns, but commercial manufacturers often use metal as a permanent part of the gun to comply with the law.

Proposals to extend the law have languished for months. The Obama administration and congressional Democrats want an extension to also take into account the new technology, by making all guns be required to contain metal in the functioning parts of the firearm.

The White House said it supported reauthorization of the "commonsense gun safety" measure.

"But Congress should work to close any loopholes that make it possible to evade the law with new technologies," said White House spokesman Matt Lehrich.

Sen. Charles Schumer, D-New York, is sponsoring a one-year extension of the law, arguing it would give lawmakers time to come up with a new measure that would tighten the rules to require metal parts in guns.

Schumer has said he'll try to get his bill passed next week.

"The House bill is better than nothing, but it's not good enough," Schumer said. "We absolutely must close the loophole that allows anyone to legally make a gun that could be rendered invisible by the easy removal of its metal part. Under current law, it is legal to make a plastic gun so long as it has some metal in it, even if it is easily removable. The bill we'll try to pass in the Senate would fix that."

Republicans say Democrats are refusing to work with them to pass a longer-term extension of the law.

"The (Democratic) majority is playing politics with public safety," Iowa Sen. Charles Grassley said last week after Democrats tried a legislative maneuver to pass Schumer's one-year extension.

"It doesn't meet the common-sense test to only reauthorize an extension of the Undetectable Firearms Act for a short year," Grassley said.

With the Senate out on a break and not returning to work until Monday, it remains unlikely legislation will be ready to take its place.