I have a 16" barrel with a 12" rail and have been thinking about getting a reflex type suppressor, either the AAC SPR/M4 or the Surefire FA556AR.  It looks like the Surefire flash hider will fit my set up (it needs 2.75" of clear barrel to fit, and I have a little over 3.25" available), what about the AAC mount for the SPR/M4?  They don't really have any specific info on how much barrel is needed to mount that flash hider and can.

Also, I'm leaning more towards the Surefire, but would like to know more about the AAC, if anyone has experience with both.  I want a reflex type suppressor to minimize my overall length because I'm already bound to my state's unfriendly NFA attitude regarding barrel length.  Also, I think they look cooler  These two seem like my obvious candidates.

I have the Noveske 16" Light Recce w/ VIS (12" Vltor monolithic upper). I have the AAC SPR/M4 flash hider installed on it. I have about 1" (maybe closer to 3/4") gap. So yes, there will be room for the SPR/M4 can (at least on my specific setup).

This might help you figure it out:

http://crankylabs.com/albums/nfa/sprm4_lengths.sized.jpg

Thanks guys!

I had a 12 inch DD Lite Rail on a bushmaster with an SPR/M4 and never had an issue with the setup