An electrical switch including: a body; a mass element; a spring element attached at one end to the body and at another end, at least indirectly, to the mass element; and an inclined surface upon which the mass element moves from a resting position to an all-fire position. The inclined surface being inclined with respect to a firing setback acceleration. When the body experiences the firing setback acceleration, the mass element travels at least across the inclined surface against a force of the spring element to contact an electrical contact and close a circuit.