The magnometric guided charge is an adapted weapon employed shortly before the battle of Wolf 359 in 2367. It was used to flush the USS Enterprise-D from a nebula by firing projectile warheads containing magnetically guides charges,  each explosion releasing a charge and subsiquent magnetic schockwave which slightly magnetises all metallic objects within its radius allowing for slow but gradual magnetisation of the hull. Eventually allowing the affected objects to be more accurately pin-pointed with each detonation.[1]

  1. Star Trek: The Next Generation - "Best of Both Worlds"