Google the MK-19 Mod. 3
This is the industrial strength granade-launching machine gun zombie killer. You can select from about 8 types of ammo from high explosive to armor piercing to anti-personnel. Instant hell at the pull of the trigger!!
"Features: The MK19 40mm machine gun, MOD 3 is an air-cooled, disintegrating metallic link-belt fed, blowback operated, fully automatic weapon and is crew transportable over short distances with limited amounts of ammunition. It can fire a variety of 40mm grenades. The M430 HEDP 40mm grenade will pierce armor up to 2 inches thick, and will produce fragments to kill personnel within 5 meters and wound personnel within 15 meters of the point of impact. Associated components are: MK64 Cradle Mount, MOD 5; M3 Tripod Mount; and the AN/TVS-5 Night Vision Sight. The MK19 also mounts in the up-gunned weapons station of the LVTP7A1 model of the AAV and vehicle ring mounts"
-Reid