EMP rifle

From Halopedia, the Halo wiki

This article contains information about a non-canonical subject that, while official, is not part of the established Halo universe.

The EMP rifle is a support weapon seen in concept art for Halo Wars. The weapon is an Insurrectionist infantry weapon that generates an Electromagnetic Pulse. To use the rifle, one must wear a charging backpack that features a large, metal dish. The dish collects and focuses static charge and transmits this to the weapon. The charge is converted into an EMP beam, which is then shot out from the rifle and used to disable electrical systems.

Variants of both the focusing prongs on the front of the rifle and the charging dish seem to be used by the X23 NNEMP Cannon, another EMP rifle utilized by the UNSC.