A warhead includes a casing having a removable front portion, a plurality of explosive segments positioned in the casing, a plurality of spacers positioned in the casing and separating the plurality of explosive segments from each other, and a removable piston configured to be inserted inside the removable front portion of the casing, wherein the removable piston pushes against the plurality of explosive segments to create a continuous segment. The removable piston may push against the plurality of explosive segments to close the plurality of spacers and move the warhead from an off position to an on position. The continuous segment may be above an explosive failure thickness in the on position. The continuous segment may be configured to detonate upon reaching the failure thickness.