Urban combat is especially dangerous because city streets offer an enemy endless places to hide. Alliant Techsystems’s new shoulder-fired semiautomatic gun removes that advantage, allowing soldiers to essentially shoot around obstacles. The XM25 doesn’t curve its bullets. Rather, it programs them to explode at precise distances. The soldier measures the distance to a target using a laser site and then dials in where the bullet should explode, such as at the corner of a building, raining down shrapnel. The bullet has a small magnet inside that lets it generate AC current as it spins and a microprocessor that measures those current oscillations to derive how far it’s traveled.