On Friday, the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) issued an open letter on the use of pistol stabilizing braces such as the Sig Sauer SB15, stating that “any person who intends to use a handgun stabilizing brace as a shoulder stock on a pistol (having a rifled barrel under 16 inches in length or a smooth bore firearm with a barrel under 18 inches in length) must first file an ATF Form 1 and pay the applicable tax because the resulting firearm will be subject to all provisions of the NFA.”

“ATF has previously determined that attaching the brace to a firearm does not alter the classification of the firearm or subject the firearm to National Firearms Act (NFA) control,” the letter reads. “However, this classification is based upon the use of the device as designed. When the device is redesigned for use as a shoulder stock on a handgun with a rifled barrel under 16 inches in length, the firearm is properly classified as a firearm under the NFA.”

“The NFA, 26 USCS § 5845, defines ‘firearm,’ in relevant part, as ‘a shotgun having a barrel or barrels of less than 18 inches in length’ and ‘a rifle having a barrel or barrels of less than 16 inches in length,'” the letter adds. “That section defines both ‘rifle’ and ‘shotgun’ as ‘a weapon designed or redesigned, made or remade, and intended to be fired from the shoulder….’ (Emphasis added).”

Read the letter in full here.

[h/t to NRA-ILA]