I am thinking about putting one of these on my post-ban M4/SIR vs. Ace's ARFX stock (have an A2 stock on it now). I like the ARFX, but am concerned that it leaves the buffer tube exposed to potential damage (foam cover notwithstanding). I like the fact that the ARBT has an overtube to protect the buffer tube.

Ace's site states "Note: The ARBT has not been ATF approved for post-ban rifles. Check all Local, State and Federal laws before installation." Anyone have any clarification on this?

Answered my own question... called Ace, and no, the ARBT was not approved for post-ban, but they will be producing a new version that *should* be post-ban compliant. The new ARBT should be available in 6-8 weeks.