What energy transformations are in a paintball gun?

Answer 1

If you are using a CO2 tank there is an endothermic reaction that takes place as the liquid CO2 in the tank boils off to go into the marker as a gas

If you are filling a HPA tank there is a exothermic reaction that takes place as the air is packed into the tank.

For both HPA and CO2 there is an endothermic reaction that takes place whenever you shoot as the gas expands, this is why, on cold days moisture will accumulate on a marker if you shoot it enough.

Every time you shoot there is a transformation of potential energy to physical energy as gas pressure is turned into forward momentum to propel a paintball

if your marker is an electronic marker the battery has stored chemical energy that is turned into electrical energy that is used to create physical energy to move various parts of the marker

If it is a pump you are part of the system applying physical energy to pump the marker and store physical energy in a spring converting it to potential energy