The Supreme Court rejected two cases challenging federal regulation of gun suppressors Monday, just days after one such accessory was used in a massacre that left 12 dead in a Virginia Beach municipal building.

Suppressors, which are commonly referred to as “silencers,” are tightly regulated under the 1937 National Firearms Act (NFA).

Both cases arose from the same transaction in Kansas when a disabled veteran called Jeremy Kettler purchased a silencer at Shane Cox’s military surplus store. Silencers must be registered with federal authorities and are subject to a $200 excise tax pursuant to the NFA. Kettler and Cox failed to comply with those requirements, so they were charged and convicted in federal court of selling and possessing unregistered suppressors. Both men received probation.

On appeal, Kettler and Cox argued that the NFA exceeds Congress’s taxing power. Lawyers for Kettler told the justices in legal filings that NFA taxes and fees are “an unabashed gun control measure in purpose and effect, bearing virtually no resemblance to a ‘tax’ designed to raise revenue.”

Kettler and Cox also argued that the Second Amendment protects silencers, citing press accounts reporting that there are 1.3 million registered silencers in the U.S. The 2008 D.C. v. Heller decision said the Second Amendment protects weapons “in common use at the time.”

The 10th U.S. Circuit Court of Appeals rejected those arguments, prompting an appeal to the justices.

The Supreme Court upheld the NFA against a similar challenge in a 1937 decision called U.S. v. Sonzinsky, but Kettler and Cox said the underlying rationale for that ruling has eroded.