Watch this update by Reapers Airsoft on this Arcturus AK01 AEG as he list the parts he used in this process... "Hello everyone, here is a little video about the update of the Arcturus AK01 with Gate Aster V3, G&G Shell, Begadi Pistonhead, Retro Piston and Begadi HopUp. Gears are used 13: 1 with 12Z Stroke and combined with a 19K Mamba."