A vet friend of mine (whose other story of drug use is discussed in a recent thread) told me how he and his buds (heh) in the war would empty the chambers of a shotgun, rack it, tilt it upward, tuck a screen down the end of the barrel, put ball of opium on the screen, light it and pass it around taking drags from the breach. Naturally enough they called this shotgunning.
In my experience, entirely divorced and unaware of that, “shotgunning” was when you were using a bong with an extra air hole, which you covered up while inhaling hard, and released it, blasting in a whole new mess of rushing air.
I think, after my hash and pot use time, “shotgunning” is/was used for a similar effect but with different physical setups–something with water levels?
Does the etymology date to Vietnam, where its derivation is unambiguous?
I saw Platoon a long time ago, and ISTR some kind of important metaphor/symbol when drugs were smoked through the barrel, obviously a more dramatic image.
Can’t speak for others, but in my SoCal circle of friends in the sixties, “shotgunning” was taking a lit joint and turning it around so the burning end was in your mouth and then gently blowing out so a stream of smoke came out of the end of the joint in your lips and another person would come up close and suck in that stream of smoke. No apparatus involved.