A three-judge panel with the Fifth Circuit Court of Appeals just issued a limited preliminary injunction to block the enforcement of the new rule from the Bureau of Alcohol, Tobacco, Firearms, and Explosives on stabilizing braces for large AR-style pistols, Breitbart reported.

In addition to the limited injunction, the panel of judges also ordered the case, known as Mock v. Garland, to be fast-tracked with regard to oral arguments on the merits in light of the impending deadline for the ATF's new pistol brace rule to take effect at the end of the month.

The ATF's pistol brace rule

In January, and without any explicit authorization from Congress, the ATF issued a final rule that reclassifies certain firearms equipped with a stabilizing brace as a highly-regulated "short-barreled rifle" if the weapon's barrel is shorter than 16 inches, when previously such firearms had been classified as minimally-regulated "pistols" for the past decade.

The reclassification places those particular weapons under the auspices of the federal National Firearms Act of 1934, meaning they must be registered with the federal government and a $200 tax must be paid.

The ATF set a deadline of May 31 for all owners of stabilizing brace-equipped firearms to either register that weapon, replace the barrel with one longer than 16 inches, detach and dispose of the brace, or turn in or destroy the entire firearm altogether -- or else risk felony prosecution for illegal possession of an NFA item.

Limited injunction granted, case expedited to oral arguments

A lawsuit was immediately filed by two individuals, a firearms company, and a Second Amendment advocacy group known as the Firearms Policy Coalition, but the suit did not fare well in a federal district court in Texas and was thus appealed to the Fifth Circuit based in New Orleans, Louisiana.

The three-judge panel that considered the appeal was comprised of three Republican appointees -- one from former President George W. Bush and two from former President Donald Trump -- who appeared to be more favorable to the plaintiffs in granting a request for an injunction, albeit seemingly limited to just them, and fast-tracking the case toward a hearing on the merits.

"IT IS ORDERED that the appeal is EXPEDITED to the next available Oral Argument Calendar," the panel wrote and added, "IT IS FURTHER ORDERED that Appellants’ Opposed Motion For a Preliminary Injunction Pending Appeal is GRANTED as to the Plaintiffs in this case."

A "huge victory," though potentially limited in scope

According to The Reload, the ATF declined a request to discuss the Fifth Circuit's ruling and simply stated through a spokesperson, "ATF is unable to comment on this litigation related to short-barreled rifles."

However, a gun rights advocacy group that had filed an amicus brief with the court in support of the plaintiffs, the Gun Owners of America organization, told the outlet, "This injunction is welcome news, but due to its limited nature, we still need Congress to act before the June 1st deadline."

A senior attorney for the Firearms Policy Coalition, Cody Wisniewski, said of the ruling in a statement, "We are very excited and encouraged by the Fifth Circuit's decision this morning."

"We intend to ask the Court for additional information about who is covered under the injunction, but cannot stress enough just how important this decision is," he added. "The fight is far from over, but this is a huge victory in the battle against the ATF's unconstitutional and unlawful brace rule!"

Next hearing appears to be scheduled for June 29

The FPC has argued in the lawsuit that the ATF's arbitrary and unauthorized reclassification of "braced pistols" to be "short-barreled rifles" is a violation of both the U.S. Constitution and the Administrative Procedure Act, as well as that it will transform potentially tens of millions of gun owners into felons overnight simply for possessing a firearm that the ATF itself had previously deemed to be perfectly legal and acceptable for the past decade.

The organization noted separately that the Mock v. Garland case appears to have been calendared for oral arguments on June 29 -- nearly one month after the ATF's rule will have gone into effect unless it is clarified that the injunction's protection against enforcement extends beyond just the named plaintiffs in the suit.