MAC discusses the most recent ATF-related hubbub, Sig Brace 15. There has been some talks about letter that ATF wrote to some entities.
Originally, SB15 was approved by ATF since the intent was to be used as an arm brace. After some letters were sent back and forth, more confusion arose and MAC talks about the controversy
https://www.youtube.com/watch?v=TYx3A80aBi0
From: Military Arms Channel