Hello! I'm neck-deep in concept designs, and honestly, I am swamped. I'm participating in an experiment to launch a rubber stopper from a bottle using a gas-producing reaction. My most recent design structure used dry ice, and a chamber made of metal, with the dry ice proportioned out inside both the chamber and the bottle to match the pressure on the inside of the bottle as the dry ice expanded. This allowed me to restrain the stopper, and build up pressure inside the bottle without bursting the bottle. This, however, apparently classified as "a bomb", and was consequently banned from use in the experiment. My question is what I should do now. I would like to launch this rubber stopper over 100-150m. The stopper (made of rubber) weighs about 85g, and the base is ~1.45cm wide, with the rest coning out to a diameter of ~2.65cm, and the only thing allowed to launch the stopper is a gas reaction, either physical or chemical. I'm launching it from a plastic 125mL bottle, with a cap ~1.85cm wide. A regular baking-soda-vinegar reaction doesn't launch it more than ~50-60m. Any ideas on how to achieve this?