Final answer:
Ammo item detonation or deflagration is determined by its sensitivity, which is a measure of how easily it can be activated by impact, friction, heat, or other stimuli.
Step-by-step explanation:
The ease with which an ammo item detonates or deflagrates determines its sensitivity. Ammo sensitivity is an important factor in determining how it reacts upon impact, friction, or exposure to heat. Caliber refers to the diameter of the bullet, velocity is the speed at which it travels, weight is how heavy the item is, and sensitivity relates to how easily it can be set off by external factors.
In the field of ammunition and explosives, sensitivity is a crucial chemical property to consider. It affects handling, storage, and the overall safety of the ammo. Sensitivity is not to be confused with the physical properties like weight or caliber, nor with the performance characteristic such as velocity. It specifically correlates to how reactive the substance is to ignition or other stimulus, reflected in scales like the one ranging from '0 - Stable' to '4 - May detonate'.