Being a basically curious guy I always have liked to take apart things to see what was inside and made them tick. Awhile ago, I bought a quantity of motley Amber M21A1 Ground Signals and in all my books I never saw a diagram of what was inside. I popped the top off of one and pulled out the parachute, but could not pull out the flare the easy way. So surgery was called for and I decided to cut it open and section it for display. Before you all scream IDIOT!! I took precautions to do this outside, far from the house, with goggles/gloves on and using a hand hacksaw only. It only took two quick, cuts down each side of the aluminum body for it all to pop open and all secrets were revealed. So after removing all of the dangerous materials and replacing them with plumbers epoxy. Here are the results.

If you are curious the sequence of events for this signal is. Rifle fires with blank and signal is discharged from end of rifle. Flame from rifle also shoots into base of signal and ignites time delay, powder train embedded in base. After powder train burns into signal, a small disk of propellant explodes, not only popping the signal out of the tube, but lighting a fuse on the flare itself. After parachute opens and fuse burns into the flare, it ignites and burns as it floats to the ground. A very clever design. I now use this as a display item, with the rest of my ground signal collection and it gets a lot of attention. BTW.

After 60 years, the flare which is basically a cardboard tube filled with powder, was massively bloated and was wedged inside the signal. This made it impossible to remove the easy way.

Please do not try this operation yourself as it is very dangerous and you may get serious hurt.

WWII, M21A1 Ground Signal, Sectioned sample