IM meaning in Military and Defence ?

Insensitive munitions are munitions that are designed to withstand stimuli representative of severe but credible accidents. The current range of stimuli are shock (from bullets, fragments and shaped charge jets), heat (from fires or adjacent thermal events) and adjacent detonating munitions. A munition can have its vulnerability reduced by a number of means used on their own or in combination such as a reduced vulnerability energetic material, design features, additions or changes to packaging etc. The munition must still retain its terminal effect and performance within acceptable parameters.