Re: Free float fore arms for Armalite AR-10
The following companies offer FF tubes/railed HGs for the AR-10 in various sizes ranging from carbine to extended rifle lengths:
1) Armalite;
2) SWS;
3) Daniel Defense;
4) Larue Tactical;
5) JP Enterprises;
6) PRI;
7) Badger Ordnance;
8) Midwest Industries.
I am sure that I am missing one or more, but that's a good start for you to look into. The only one of those that I call into question in terms of quality would be the MI offerings and only because I have not had a chance to personally inspect, install or otherwise use one of the MI handguards yet to offer an informed opinion on them. All the others are of excellent quality.
As for PRI, I have not used their rifle length AR-10 handguards, but I have one of the Armalite AR-10 Carbine units installed and I like it a lot. It is light, very solid and fits my needs well. I have used PRI's AR-15 rifle-length HGs and have always found them to be excellent, so along with my experience with the AR-10 carbine HGs, I am comfortable recommending the AR-10 rifle-length units without a doubt.