Screenshots of what you're doing.

Edit: Nice gun, Nowego4 but:
There seems to be too many things attached to it.
I know that its multitask weapon but paint roller on the top of it? (paint splashes as a secondary).
The arm support looks like prosthesis. I think that's funny.
The end of the cylinder (where bullet/water/paint comes out) looks strange

Agreeing with his critique.

The gun looks way to elaborated for a game like Xonotic.

I'd strip it of all the parts that are sticking out, make some sort of energy tank thing at the back instead of that unnecessary reload mechanism, and have it put in the game as a lightning gun or something else (maybe after tweaking the front part a bit).