Non-electric explosive device and method of severing a tubular

A method of severing a tubular, comprising:

• assembling a non-electric explosive device by attaching an explosive body including explosive material to a first axial end of a primary body, the primary body containing cutting material and including a primary charge positioned in the cutting material, and attaching a firing head to a second axial end of the primary body, the firing head including a firing pin secured at least partially inside the firing head via securing device, the firing pin comprising an activating end proximate the primary charge and a blunt end protruding from a distal end of the firing head;
• dropping the non-electric explosive device into the tubular with the firing head facing downward so that the protruding blunt end of the firing pin impacts a bottom of a well containing the tubular, or a tool in the tubular;
• and
• causing, via impact of the blunt end of the firing pin, the firing pin to retract toward the primary charge and break the securing device so that the activating end of the retracting firing pin impacts the primary charge, which ignites the explosive material and creates a blast that propels the cutting material in the primary body radially outward and through a wall of the tubular.