Various ultra-miniature, monolithic inertial switching (G-switch) devices used in safety and arming (S&A) devices for projected munitions, which operate in accordance with a shuttle member (50), which effectuates current switching of around an ampere of current when subjected to a threshold inertial loading (for example, an impact or gun launch of a projection munition). The embodiments of the invention can be a passive threshold G-switch with or without switch enable and arming capability. The embodiments (100, 200) of the invention use either mechanical or electromechanical switch enable functioning and can optionally include a shuttle time-delay feature (54). Both embodiments can incorporate various designs for a switching assembly (75) such as latching single-throw switch having the configurations of either a normally-open, double pole, single-throw switch or a normally-open, single pole, single-throw switch, wherein switch closing occurs when the shuttle member (50) experiences inertial loading and penetrates the switching assembly (75).