I am wanting to buy a 20in upper with a free float handguard. The upper I have been waiting for from BCM (http:\/\/www.bravocompanyusa.com\/BCM-20-Rifle-Upper-Receiver-MI-p\/bcm-urg-std%2020%20mi%20ss15.htm) has been out of stock forever. PSA just put up a 20in upper(http:\/\/palmettostatearmory.com\/index.php\/psa-20-hammer-forged-madness-stripped-upper-without-bcg-or-charging-handle.html) that is in stock at the moment. My question is what would I need to add a free float. I know i need a low pro gas block with correct gas port size and obviously the handguard. I want the MI SS15g2. Also what is the difficulty. I have never done a free float just standard. Thanks in advance.