The Auto Shotgun is a Special Forces drum-fed shotgun you get free from the Horde Killer storyline. It fires shells as fast as you pull the trigger. It is one of the best close-range tools for Freaker crowds and Breakers.
Clear 10 Hordes to reach 25% of Horde Killer. Hordes in the north, such as caves around Belknap, are the easiest way to get there early.
It shreds Freakers at close range and staggers Breakers with rapid shots. It is also strong against human enemies charging your cover. At range the spread wastes shells.
The Liberator is also semi-automatic but holds fewer shells. The Crowdbreaker carries more ammo but fires slowly. The Auto Shotgun gives the best damage over time of the three.
IDF Pup
The IDF Pup is a Special Forces bullpup rifle you get free for clearing Hordes. It unlocks at 50% of Horde Killer with a 45-round magazine. It is accurate, fast and one of the best primaries for Horde fights.
MG55
The MG55 is a Special Forces medium machine gun with very low recoil. It unlocks free at 60% of Horde Killer and goes in the special slot. It is the best machine gun for taking a Horde apart.
SMP9
The SMP9 is an automatic sidearm with a 30-round magazine. You can buy it at Hot Springs or Lost Lake, or get a better Mil-Spec copy free from Horde Killer. Full-auto in the sidearm slot is great on the bike.