Machine Gun Kelly lets loose with plenty of ammunition, spitting furiously and with something to prove on the Rage Pack mixtape.

Sampling “We Got The Beat” from The Go-Go's on “STFU," the Cleveland, Ohio native doesn’t hesitate stating everything he despises on his aggressive, yet catchy opener. “Shut the fuck up with your wanna shake my hand, ass/With your, Hey white boy let me hear you rap, ass/With your 45-year-old, trying to be my fuckin' ma, Pull up your pants, ass,” MGK raps with scorn.

From there, the self-proclaimed PowerRager and Bad Boy Records new blood continues rhyming with high-energy and vigor on tracks such as “Wild Boy” featuring Waka Flocka, “Warning Shot” and the warped-sounding “Welcome To The Rage,” on which MGK takes hip-hop through a raging mosh pit. (Between that, Diddy scolds MGK on the humorous “The Morning After Voicemail” for thrashing his crib and drinking all his Ciroc).

While “Fantasy (DIGIRAATII)” may have MGK going too left field with a trans/house vibe that the cast of the Jersey Shore would probably dig, it also shows that the young gunner isn’t afraid to experiment and take chances with his sound. The 12-track offering doesn’t round out before Kelly tabs Mike Posner for “On Fire (Drug Dealer Girl II),” a nice sequel to Posner’s own original "Drug Dealer Girl."

Rage Pack is an apt warm up, concise enough to leave the listener wanting to hear the rest of MGK's story, but full enough to prove Kells has plenty of bars in his chamber, steady sharpening his aim for his upcoming debut album. Lace up! —Mark Lelinwalla