Step 7: Why doesnt my spud gun fire?
You loaded a projectile that fit right, filled the chamber with a good propellant, sealed the chamber, and hit the igniter but the propellant doesnt ignite and nothing has exited the barrel but can see a spark leap across from one wire to the other when you squeeze the igniter:
You put too much propellant in the chamber resulting in a fuel content too rich and dense to ignite by ghetto means. Depending on the propellant, chamber, and other small, meticulous variables the air fuel ratio has to be ideal to be able to ignite. Its hard to measure the propellant content by any reasonable means so the remedy given is not a sure-fire thing but with practice the process can be somewhat reliable. Spray a small amount of propellant in the chamber, use your reasoning abilities on determining how much is a small amount and if it fails experiment logically knowing that if you spray for X-milliseconds/amount-of-time (you dont need to keep track) and if it doesnt ignite, purge the chamber by blowing through the chamber (unloaded, no projectile) with a moderate amount of force until satisfied and sure enough that there is no gas in the chamber that can alter the series of trials and errors (unless youve found the divine method) and spray again with an amount a little less propellant and repeat until successful. Ive experienced the best performance by quickly pressing the spray button all the way down and immediately releasing it and then gently blow into the chamber. It takes a few tries until you get it right but its the best way I know how.