SIG’s extended muzzle brake is, in the eyes of the law, a suppressor component. The U.S. District Court of New Hampshire upheld the lower court’s ruling in favor of the ATF. “[The] gun SIG Sauer seeks to market includes a ‘silencer’ under the National Firearms Act,” reads the ruling.
Announced at SHOT Show 2013 and put into production about a year later, SIG’s permanently-attached muzzle device has always been a little controversial. It was originally touted as a brake that could be converted to a suppressor with a threaded adapter sleeve. The idea was that SIG could sell the MPX carbine and customers could buy an adapter separately. This would give shooters the instant gratification of getting the carbine right away and let them get in the NFA-waiting line in their own time.
It was marketing genius, and an engineering solution to a regulatory problem. By permanently attaching the muzzle device to the barrel, the MPX brake also brought the overall barrel length to over 16 inches long, preventing the gun from being NFA-regulated, too, as a short-barreled rifle. The suppressor adapter was to be the only NFA-regulated component.
Whether the brake legally counted as a suppressor component was up for debate immediately. The ATF quickly determined that it was indeed part of a silencer, making it an NFA-regulated component by itself. SIG filed suit against the ATF’s determination in 2014 and, late last year, lost their first lawsuit.
The appeals court agreed with the lower court’s ruling and agreed with the ATF. The ATF’s case argued that the device did not function “safely” without a sleeve, and that installing a sleeve effectively made it a silencer.
The MPX has a handguard that extends beyond the first baffles of the muzzle device. This is why the ATF determined that the device was unsafe and required a sleeve; the gasses leaving the muzzle were directed toward the shooter’s hand, putting the user at risk. In a certain light, it may seem like the ATF determined that the device was a suppressor — after converting it to a suppressor.
SIG may decide to press the issue further, although there are other reasons the appeals court ruled in favor of the ATF. “Further supporting ATF’s finding that this part is a monolithic baffle core is … that this part is identical to the monolithic baffle core that SIG Sauer uses as the interior of the complete silencers that it sells; that SIG Sauer used the same part number to identify the part in question here and [for] the core of its removable silencer; that SIG Sauer labeled this part a ‘silencer’ on its invoice; and that the part included threading at the muzzle end that made it easy to encase the part to produce a complete silencer.”
The court also agreed with the ATF’s arguments that the brake is unusually large, particularly for a pistol-caliber carbine, and dimension-wise, similar to monocore baffles used in silencers, not brakes. The fact that the device was threaded to accept an adapter to convert to a suppressor without modification was also part of their decision.
SIG argued that the part was oversized to bring the overall barrel length up to over 16 inches to exempt it from NFA-regulation but ultimately the court ruled that the device was designed as a suppressor component first, then re-classified as a brake. SIG had “basically taken the cap off [of its] silencer, welded it onto the gun, and [was] just going to sell it as a muzzle brake.”
The next step would be to take it to the U.S. Supreme Court, but the high court has been lukewarm towards gun-related cases recently. The Supreme Court passed on making a ruling on whether or not “assault weapons” bans are constitutional last December. The court also greatly expanded the ‘domestic abuser’ standard, by establishing that a person can lose a constitutionally-protected right over a misdemeanor crime. They did, however, toss out a finding that stun guns and other electronic arms are not protected under the Second Amendment, putting the issue back to the lower court.
Following the passing of Justice Antonin Scalia, the Supreme Court also only has eight justices, which means there are no tie-breaker judges in the case of close decisions. Scalia was a strong supporter of gun rights and a staunch originalist, sticking to the tenets of the Constitution, Bill of Rights and common law.