Kelos'vaarda-pattern storm rifle
From Halopedia, the Halo wiki
The Type-55 Storm Rifle is a Covenant weapon which first appears in Halo 4. It is a heavily modified and advanced version of the Plasma Rifle which features such modifications as a modular coil set, a high-mounted cooling shroud, and an extended barrel. It saw use during the Sangheili civil war conflicts after the Human-Covenant War.
