Combustion process

1. A cap is opened to the chamber 2. Fuel is sprayed or injected 3. The cap is shut and sealed 4. The fuel is mixed with the air 5. The mixture is ignited 6. The mixture burns rapidly until the fuel or air is all used up, increasing pressure, shooting the projectile out 7. The cap is openned again, to vent the exhaust fumes and load in fresh air