Watching the video, and the homemade RPG reminded me of a SAM my cousins and I built as kids.
1) An Estes model rocket...a WAC Corporal...with a B8-4 motor.
2) A shipping tube with a launch rod glued to the bottom cap.
3) Copper strips glued/screwed to bottom cap with wires running outside to a Burgess B battery and momentary switch from Radio Shack.
You slid the rocket down the tube on the launch rod with the nichrome igniter wires touching the copper strips. Aim, press the switch, and whoosh....a balsa and cardboard Stinger.
We didn't have the C4 and blasting caps for the warhead portion (thankfully), but we could aim and fire a $4 rocket.
The nosecone was to be built from C4 with a blasting cap on the nose and underneath. If you missed a direct impact, the ejection charge from the motor would slam a washer into the underneath blasting cap and still detonate the missile. At least that was our thinking.
Again, we never had anything that actually exploded, but something like this would probably work against low-flying helicopters. A C or D motor would give more range, etc.
Yes, we had way too much time on our hands. One of our test flights did cause 3 casualties...to a neighbor's chickens. A fin came off on launch and the rocket arced into the neighbor's chicken yard at feeding time. The rocket didn't hit the massed birds but 3 apparently died from fright. We paid for the dead birds from allowances and odd jobs.
Years later, in the Air Force, I was assigned to the USAF Rocket Propulsion Lab at Edwards AFB. I managed not to kill or blow up anything there.