A legal arm brace is a device designed to attach or support off the arm and not the shoulder. In order to be completely legal, the manufacturer had to send in the device to the ATF for a determination. A stock is designed to be supported off the shoulder. Gearhead works tailhook, sb tactical, and the shockwave blade are the 3 most popular styles of braces. If a firearm has a barrel less than 16" and a brace it is still considered a pistol. If a firearm has a barrel less than 16" and a stock it is a SBR and needs the tax stamp.

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