Question on a AR-pistol build

[jdben92883]

I have a Sig 556 w/no buffer tube, so please forgive me if this is a bonehead question. I'm going to build another pistol on an 80% lower. I have a 12" upper and a Sig SBX ordered. Can I use a regular buffer tube with this setup or do I need to get a "pistol" tube and buffer? I don't know if the pistol tubes are simply used to keep a lower profile or if they are sized a certain way to cycle properly with the shorter barrels, or etc.

Thanks!!

[Cactus_Tim]

You'll need a pistol buffer tube.
Sig SBX brace won't fit on a regular buffer tube (which accepts a collapsible stock).

Watch at about the 4min mark.