This is a schematic weapon with 501 damage plus fire damage plus radiation damage. It is built from a Nuka-Cola Quantum, tin can, turpentine, and Abraxo Cleaner. One of the schematics can be found on the bottom floor of the Yao Guai Cave, in the northwestern-most area, under a pile of skeletons. Doc Hoff sells one of the schematics, and Sierra Petrovita in Girdershade has the third, which she gives you as a reward for the "Nuka-Cola Challenge" quest. Every schematic increases the number of grenades created per set of materials, up to a maximum of three.