From: The Honorable Ruben Kihuen
Sent By:

Date: 3/2/2017

Dear Colleague:

Please join me as a cosponsor of the Undetectable Firearms Modernization Act.

Under current federal law, it is illegal to own, manufacture, or transfer a firearm that contains less than 3.7 oz of metal, or that do not present an accurate image when put through an x-ray machine. The law, signed by President Regan 1988, was intended
to ban firearms that may be able to pass through a metal detector undetected, and subsequent reauthorizations have been signed into law by Presidents Clinton, Bush, and Obama.

However, technological advances necessitate a reevaluation of the efficacy of the original law. When the Undetectable Firearms Act was passed in 1988, fully plastic guns were science fiction- now there are readily accessible plans online on how to build

In 2013, Defense Distributed published the plans for the Liberator, a plastic gun whose only necessary metal component is a household nail used as a firing pin. The gun contained a single 6 oz metal block to comply with federal law. A terrorist or criminal
could easily manufacture a Liberator, remove the metal block before entering a secure area, and walk right through a metal detector with no one the wiser. Some have said that metal detectors will be able to pick up the bullets and firing pin necessary to make
the gun lethal. However, our staffs walk through security checkpoints at least once a day, and they can attest to how easy it is to talk through a metal detector with a small amount of metal, be it their keys, belt, or watch.

The Undetectable Firearms Modernization Act would require that certain major components of a firearm (the receiver and slide or cylinder for handguns, and the receiver, slide or cylinder, and barrel for long guns) be detectable either individually
or when combined. The bill is designed to be agnostic as to which component is detectable, allowing for further innovation in gunsmithing. One gun may have a detectable metal slide and a plastic receiver, while another may have a detectable barrel and plastic
slide and receiver, while another may have no single major component that is detectable on its own but the major components when combined are detectable.

This common sense update to current law would better achieve the goal of the original Undetectable Firearms Act to keep terrorists and criminals from carrying a firearm into secure areas, while recognizing the desire by some to continue to innovate.

For more information or to sign onto the bill, please contact Mark Snyder in my office at



Ruben J. Kihuen
Member of Congress