Pack a Punched Thunder Gun. It appeared in black ops 1 and only black ops 1 it has infinite damage (no sereously look it up) but ammo is scarce due to being a pack a punched box weapon can save games and get you to round 100
P1: I'm gonna turn the power on
P2: Good I need to pack a puch my thunder gun
P1: The zues cannon will really help us on high rounds