The KWC SW40F Airsoft GBB Pistol uses a Semi Auto CO2 Gas Blow Back System and has a 26 Round full size Metal Magazine. It is a 1:1 Ratio realistic reproduction of the S&W SIGMA SW40F Pistol. The KWC SW40F also has a full metal slide & barrel assembly and is one of the more Powerful blowback CO2 offer airsoft pistol today with a 390 FPS rating The KWC SW40F has an extremely smooth slide with the operation and feel of a real gun.