Ok funny story from years gone by. My cousin and myself got a piece of gas pipe crammed it into the dirt (mud) dropped a railroad flare into the pipe and then drop a co2 cartridge on top of the lite flare. It worked great for the first two times.third time, failure to fire. waited several min picked the pipe up holding it off to the side so if it went off it wouldn't blow my head off. Well it did go off. rail road flares have a nail in their bottom so it can be mounted to a wooden rail . It drove the flare out the side that had been in the mud into my knee . i still have that indentation in my knee to this day. That was our mortar