Coming back on this guy. I finally did the head swap and finished his robot mode. 5 down, one to go.

 

First thought: "RotB Arcee?"  

 

It's a head sculp from Shapeways/Steam Shield to create Reflector out of a Legend Shockwave. Initially I had in mind to add 2 antenna like extensions above his 'ears' but when transforming into waver gun, there is hardly any place for these and they will break off. So I leave it as it is.

 

The head is not 100 % there but there's nothing really wrong with it. It's just the colors, proportions and size (and the head a bit) and the fact that I've seen the pictures of SS RotB Core class Arcee so much lately. So I immediately associated.

 

My oh my, Shockwave in that color scheme is very eye-catching