I know Chopper is faster btw, but it is maybe the fastest that is not the Chopper. So a machine gun i found in the game, legit. Just trying it out with skills that increased my fire rate. I calculated, or how you would spell it, the new fire rate: I got it to 25,11 shots per second.
Note: Yes my inventory space is modded, the pearlescent weapons are modded, not by me, to a lower level.