i have my local machine shop build a 3 x 7 x1/2 aluminum plate. then mill a radius groove down the middle ( 7 length) to match my free float handguard.
i then glue and screw it to the handguard. screws are a pain...think i may glue this one(had it built yesterday) then drill and pop rivet in place. fill the rivet holes to regain the flat smooth surface.
mike in co
If I were looking to flatten the round handgaurd for bags I would fab a flat 3 inch wide plate and attach it using picatinny rails, that way it would be a stable adjustable attachment.............Don