Showguns RX-79 Gundam Ground Type MG100 Machine Gun Kit with Fire Pig Light Tracer for Action Arm AAP-01
3D-Printing Construction (Ultra-lightweight)
Design For Covert your Pistol (AAP-01) to The 08th MS Team" the MG-100 Style Rifle
The 08th MS Team" the MG-100 was the primary weapon of the units used by the Earth Federation. 
Suitable For Action Army AAP-01 Series Airsoft Gas Blow Back GBB Pistol
Upon installation the kit is functional and items such as the wire stock and side handle are all usable (though added care must be given as they are not designed for heavy airsoft use). 
In addition, a light-up "Fire Pig" muzzle device from WoSports is included for extra realism!