This is a Cip-Quad blaster cannon from Clone Wars Chapters 20-21. It is manned by a 747th heavy gunner.
About this creation
An experimental weapon field-tested during the Clone Wars, the Merr-Sonn Reciprocating Quad Blaster, or Cip-Quad, transforms a single soldier into a mobile piece of anti-personnel and anti-armor blaster artillery. The quad blaster is mounted on an articulated and powered harness, fitted with microrepulsorlift buoyancy cells that help reduce the overall weight of the heavy cannon.-From the Star Wars Databank
Thanks. I think the flick missiles don't work well, so I built this. I would have built a Cip-Quad from Clone Army Customs, but I thought that version was too big. No offense to Clone Army Customs, though, because his ARC heavy gunner is beyond what I could ever build. I also had to cut a LEGO rod to make the joints for the harness. Please don't hate me for (I'll use my former best friend's term) "mutilating" LEGO pieces. It took me forever to find the right pieces. Thanks for the comment. TELL YOUR FRIENDS!!!