I recently purchased a Airsoft G.I. G4-A1 with a Troy 11 inch free floating rail system. The outer barrel is currently 14.5 inches long, I want to bring it down to 10 inches and the bring down the size of the rail system. I am going to use my 10 inch mock silencer to hide the rest of the inner barrel. I want to know what size rail system I should use if I put a 10 inch outer barrel on it. If you have any suggestions please let me know.