The magnetic missile was developed by the DeBruin Company in the mid 1930s, with the first prototype undergoing testing in 1935. By 1937, the magnetic missile was available for purchase by military and law-enforcement customers, although this restriction lasted less than six months.
By mid-1938, the magnetic missile had become the warhead of choice for dogfighter-type aircraft, and was considered the standard weapon for the Hughes P21-J Devastator.
The magnetic missile shared similar performance characteristics to the earlier beeper-seeker rocket, in that the gauss detector in the missile's nose allowed it to track in on large concentrations of ferrous metal. This allows the magentic missile to "home in" on targets.
While the magnetic missile does display a degree of seeking behaviour, it has a large turning circle and can only detect targets within a narrow cone directly in front. This means that it it most effective when fired at targets travelling on a parallel course to the launch vehicle.
The magnetic missile is also used in the French roquettes triple or triple-rockets system, which launches three smaller rockets at once, each with an independent magnetic seeker head.