Originally conceived in 3050 by the Free Worlds League as an electronics countermeasure attack against a targeted BattleMech's targeting and tracking systems, its designers quickly discovered that the prototype Magnetic Pulse Warhead also had the unintended side-effect of momentarily weakening the magnetic shielding of Fusion Engines, triggering a notable "heat spike" before the engine's containment returned to normal. This combination of effects led Captain-General Thomas Marik to encourage further research, authorizing field testing of the Magnetic-Pulse Warheads by the Free Worlds League Military during Operation Guerrero, and like many pieces of League technology, also falling into the hands of the Word of Blake. 
Unfortunately much like the Listen-Kill Missile before them, the Magnetic-Pulse Warhead fell prey to the hype surrounding them. As rumors of the ultimate "'Mech-stunner" quickly spreading, fusion engine manufacturers across the Inner Sphere raced to update their engine containment software to rapidly cope and adjust to external interference of magnetic shielding, greatly reducing the severity and duration of the heat spike caused by MPW. With this advantage mostly negated, the Magnetic-Pulse Warhead was left to its original role of anti-EW work, only to be superseded by less costly and more effective systems such as the ComStar developed Improved Narc Missile Beacon's Haywire Pod, and were eventually discontinued in 3065. 
The Magnetic-Pulse Warhead is manufactured on the following planets:
- Under the Tactical Handbook rules, each hit from a MPW equipped SRM raises heat by 2 for each hit, while each LRM MPW's raises target heat by 1 per hit. In the next turn after the target is struck by a MPW flight, the target 'Mech operates with a +3 penalty for any weapons to hit rolls. This penalty occurs no matter how many or how few missiles hit, and multiple hits in that turn do not increase or extend the effect, the targeted 'Mech returning to normal in the next turn. 
- Under Tactical Operations rules, a successful Magnetic Pulse Missile attack instead imposes a +1 to-hit modifier on all the target's weapon attacks from the end of the Weapon Attack Phase to the End Phase of the turn following the attack. Against any heat-tracking unit powered by a Fusion Engine, the target's heat is increased by +1 for each five LRM missiles or three SRM warheads rounded down that hit the target, the spike only lasting for the durtion of the turn in which they hit.
- Tactical Handbook, p. 59 "Magnetic-Pulse Warhead (MPW)"
- Tactical Operations, p. 370 "Magnetic Pulse (MP) Missiles"