Sig Sauer, known in the firearms legal for their willingness to litigate against the BATFE, has lost their MCX “muzzle brake” case in federal appellate court. The Appeals court agreed with the U.S. District Court of New Hampshire’s previous ruling that Sig’s MCX “extended monocore brake” was indeed a suppressor.

While US firearms enthusiasts may beman the ruling, it was hard for Sig to make an argument that the true intent of the extended brake was as a muzzle brake, not as a monocore for a suppressor (unlike that of the “arm brace”) . Per SeaCoastOnline:

In Tuesday’s decision, the appeals court agreed with the ATF that the disputed gun part is intended for use only in assembling or making a silencer because it was designed with features common to all silencers, but not muzzle brakes. The appeals court also agreed with the ATF that the part “is not of a type that requires, or is sold with, a muzzle brake” and that Sig had initially submitted a prototype of a gun, with the disputed part, that only functioned safely “if it was encased and thus had been made into a complete silencer.”

The appeals court noted that legal counsel for Sig Sauer agreed with New Hampshire’s federal court that 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.”

Basically, Sig had shown the court and the ATF that it was meant as a suppressor stack.

This is disappointing, as I believe Sig missed and opportunity and failed to use the case to compel the ATF to clarify what the definition of a suppressor truly is. Getting a solid legal definition would go a long way to clarifying the still murky waters surrounding “suppressors” including what comprises them, their parts, etc.