Parts finally arrived yesterday. Spent a few hours doing reassembly. Quite a bit of fitting is required to get one of these together after everything has been plated and poor fitting aftermarket components. Such as the FFT handguards must be filed down to get the barrel ring to seat correctly. The FFT hammer had to be ground a bit to make the hammer not hang up on the disconnector. The gas pistons have to be fit. What I do with the pistons is I put the pistons in my drill chuck, then hold a section of 400 grit sandpaper. I then finish it up with some 1000 grit paper. You keep test fitting the piston to the barrel to see when enough material has been removed.