[DarkAngel]

Yup, Chemical combustion is pretty hard to stop, sometimes removing the current will not stop the reaction process once it has started.

Tether the battery to the outside of the gun if you dont have space for a hot pack inside the gun. That way you can always throw the gun away should it start to combust and there is little to no risk to your wiring and switch assembly should the wiring get yanked (assuming you tape the wire down to the gun stock etc rather than let it float about freely)