The latest is the M118 Flex-X plastic explosives system. Around 1967 or so, when I was a kid in Chicagoland, one of the local television stations ran military films early in the morning. Could have been later, around '68, all I remember was that I was pretty young and they showed cool stuff. I cannot remember the station either. We had a lot of stations to choose from then, and I was that kid who would get up at 5AM, slowly turn the dial, and see what was out there on every channel I knew was broadcasting, as well as seeing if there was anything new on.
One of the films I remember was Soldiers identifying booby traps in the jungle, and springing them or disarming them in other ways. A few of them can be found in this CBS documentary about the Vietcong:
Vietcong Equipment and Explosive Devices. Nothing here is "secret" or "classified" at all.
The following munitions film is just over 1 1/2 minutes. The whole thing is maybe 5 or 10 min., not sure since I have not seen the full film since the mid 1960s. Oh, I was in the US Army (Guard & Reserve mostly, a little active) for 30 years and I never saw this video there, even when I had demolitions training. The only place I saw the whole thing was on broadcast television from Chicago in the 1960s.
Update: Found what looks like the full video I remember and one reference says its other name is Detasheet B.
Over the years, I asked Army Engineers and Special Forces folks if they ever heard of this stuff. But one of the problems was my youth. I did not remember the detonator needing to be attached! For some reason, my child eyes thought you just ripped off the backing and stuck the block to something, then it blew up some time later, and that is what I was asking fellow service members about. Well, they did not know of any explosive that is activated when you pull off the backing and expose it to air, and there probably isn't anything in the inventory like that now either.
As with just about everything I find online , this demolition system relates to the Time Bomber book. The bomber stated in his notes that he would be back later with more powerful bombs, made from better clocks and packed with "compact plastic explosives." The Flex-X sheets are about 14% stronger than dynamite. Regular Composition-4 (C-4) is about 30% stronger than dynamite. Both are more stable and safer to handle than civilian dynamite too.
From the video you can see, if you have this stuff there is nothing to setting it up. If you know your way around a blasting cap, you don't really need to know much else.
Ⓐ Steve Ⓐ