WASHINGTON — U.S. District Judge Wesley Hendrix ruled Wednesday that federal registration and recordkeeping requirements for firearm suppressors and short-barreled long guns are unconstitutional, dealing a direct blow to a pillar of the 1934 National Firearms Act.

In his 66-page opinion, Hendrix said the NFA no longer generates revenue from untaxed firearms and therefore cannot be sustained under Congress's taxing power — the constitutional hook the law has relied on for nine decades.

Hendrix sits on the federal bench in the Northern District of Texas. President Trump appointed him to that seat.

If the ruling stands, federal registration requirements for the sale or transfer of suppressors and short-barreled long guns would be erased, removing a tracking tool the Justice Department and other federal agencies use to monitor those weapons. Gun owners and manufacturers of the affected items would face fewer federal hurdles to acquire or transfer them.

Hendrix delayed his order by one week to give the federal government time to appeal.

Congress enacted the National Firearms Act in 1934 during rising gang violence. The law sought to control access to machine guns, short-barreled rifles and shotguns, and firearm suppressors through taxation and registration.

The decision hands gun rights advocates a new legal argument for challenging other federal firearms regulations built on the taxing power. Courts in other circuits may look to Hendrix's revenue-generation analysis when weighing similar cases.