What component typically provides a ground for the electrical firing circuit in impulse cartridges?

The case of an impulse cartridge typically provides a ground for the electrical firing circuit. In the design of these cartridges, the case is made of metal, which serves as an excellent conductor and is connected to the ground of the electrical system. This grounding is essential for completing the circuit needed to fire the cartridge when electrical current is applied.

The other components, while crucial to the function of the cartridge, do not serve the same grounding purpose as the case. The fuse is part of the safety mechanism to prevent unintended discharge, the primer contains the explosive compound that ignites the propellant, and the shell contains the projectile and the other components but does not provide the electrical grounding needed for the circuit.