This is the Bandai HG 1/144 Light-Type Guncannon [5068593]

The Light Cannon from "Mobile Suit Gundam GQuuuuuuX" is now joining the "High Grade (HG)" model-kit lineup from Bandai! It's posable so it can get into just about pose you can think of; it's armed with a rifle and a saber, and the cannon is movable on one axis. A set of flat hands are included. 

Includes

• Weapons (x1 set)
  
• Hand parts (x1 set)
  
• Stickers