I posted this in GD. If you like to shoot BP than this is for you.

I am testing some  lighter loads for a soda can mortar.  Every thing is homemade except for the tube itself. The ignition system is a clothes pin switch.
BP load is about 2/3 and cans weigh in about 10 oz. They fly about 200 ft . Angle was about 60 degrees. These are the loads for when my grandson shoots it.
Very safe limits. Another bonus is he will have to retrieve the can before he can shoot another round. Better than him playing with the electronics.

https://youtu.be/Ilwv_HM08sk

This other video is same light load but I shot closer to the mortar and only capture the ignition and shoot. I also slowed it down to .125 to get a better idea of what is happening.
I need to do some night shooting and record.

https://youtu.be/chw9DlX66io

That's pretty
Ban soda cans now, before it's too late

awesome.

More details on the ignition system?

From the cannon working back. Black match(100% cotton string soaked in BP dust slurry) set off with a piece of nichrome 80 wire 30 awg wrap around
outside end of the black match. I use a piece of painters tape with a sprinkle of bp folded over the wire and fuse for a hotter light off of the fuse.
I have 20 feet of copper wire with small alligator clips attach to the fuse wires. I modify a clothes pin to act as a snap switch. I use a piece of string attach to a small piece of wood
which holds open the clothes pin switch. The other end of the copper wires is attatch again by alligator clips to a 12 volt battery(I use my 4wheeler).
Pull the small small piece of wood out by pulling the string causes the clothes pin switch to close and ignite the black match.

I was called MacGyver  years ago at one of my jobs.   I came up with out of the box ways to get us out of a bind.
I will take pictures in a couple of days. Pictures are worth a thousand words better than me describing it.