These are scans from the US Army Technical Manual "Improvised Munitions Handbook". I used to have a copy myself. Specifically written in the '60s or '70s to help the "freedom fighters" rise up against the communist oppressors. Also for the "clandestine special forces" behind enemy lines to stir up mayhem and foster revolution. Seem to recall that from the preface. TM 21-210 or something similar. Ah just looked it up - 31-210. Memory serves me reasonably well!
I made one of those "zip guns" years ago as a teen and the experience wasn't good. Smashed finger, ringing ears, scared shitless. Don't recommend it to anyone! The smoke grenades and flares can be fun, however!
Do keep in mind the intention of the original publication.