I have an AR10 Carbine that I want to free float and am curious what the hive would suggest as far as options and length. I definitely want something that will give me an uninterrupted 1913 rail. So far the VTAC Extreme Battle Rail in 13" is what I'm thinking. I can't seem to find any designation on their site for AR15/AR10 though, does their rail fit both?
I would suggest a PRI lo-pro gas block and the ArmaLite rifle length free float railed hand guard.
PRI gas block
AR-10 NM Free Float hand guard
I like the DD Lite Rail. I don't have them on my AR-10, but I have them on my 6.8. When I have the cash I will probably get the 12 inch, right now the (little)cash is going to ammo and mags.
I used the SWS rifle length FF Rail. This rail, IMHO is the best rail out there for the AR-10 platform of rifles and carbines. here is a picture of my carbine with a SWS rail.