Sonic shell
Warpath is capable of loading up his main gun with several different kinds of shells. Presumably, when he loads a sonic shell into it, it becomes a sonic gun.
Fiction
Decepticon Poison
Warpath joined Optimus and a few other key Autobots on a mission to destroy the Decepticon Poison Lab. Warpath was the one to take the final shot, using his sonic gun to create a sonic boom, destroying every single beaker in the lab. Decepticon Poison