SIG Arm brace question

[Thompson9494]

I apologize if this is in the improper section!

I just had one question regarding the SIG Arm Brace stock. I have heard from several folks that shouldering the arm brace is perfectly legal and sanctioned by the ATF and have also heard from several people that shouldering the arm brace could land you in serious trouble with the ATF if you are caught doing so.

So is shouldering an arm-brace 'pistol' illegal?

Any information is appreciated, thanks!

 

[ugaarguy]

As of 10 Nov 2014 BATFE says shouldering the arm brace turns the gun into an SBR - http://www.thehighroad.org/showpost.php?p=9739487&postcount=241.

Full ongoing discussion in legal - http://www.thehighroad.org/showthread.php?t=756511.