When a handgun just won't do the trick, an armgun is what you need. (Firing this beaut for twelve seconds costs an arm and a leg.)

Barrel spins, bandolier has jigglebones.
http://gfycat.com/TidyInnocentArkshell
http://gfycat.com/ImprobableScaryFoxhound

CREDITS:
Concept art - Metabolic
Model, texture, promo renders - Constructor
Jiggle bones, animation, other dirty work - Svdl


Created as a submission for Arms (heh) Race 2.

[facepunch.com]