Gun Wiki
MPX brace demonstration

A SIG MPX's pistol brace being demonstrated by an instructor from SIG Sauer

A stabilizing brace, also known as a pistol brace or an arm brace, is an accessory for some modern firearms on the civilian market. It is a replacement for the buttstock, and is primarily designed to help the shooter fire their weapon one-handed.

The brace is fitted with adjustable straps in order to tighten it around the shooter's forearm, helping increase accuracy and reduce recoil during single-handed firing. A brace can alternatively be used as a traditional stock.

Since 2012, firearms with barrel lengths below 16 inches and fitted with braces were legally considered pistols. In 2015, the ATF ruled that shouldering the brace of a weapon with a short barrel constituted a "redesign" of the gun into an SBR. This later changed in 2017, when the ATF reissued a letter stating that firing a brace-equipped weapon from the shoulder wouldn't make it an NFA firearm anymore.

In January 2023, the ATF issued a rule stating that brace-equipped weapons with barrels under 16 inches would be legally SBRs. This regulation has however been overruled in June 2024.