The Grenade Launcher is located in the Training school in the Art storeroom. It takes up 2 spaces of inventory and is compatible with three different types of ammunition: Grenades, Napalm Grenades, and Acid Grenades. Billy can fire the weapon faster than Rebecca. Its ammunition is uncommon and is usually only provided to fight specific upcoming enemies. It can hold a maximum of 240 rounds of the same type (however it is not actually possible to obtain that amount of ammo). (Wiki).