40mm XM664 Star Cluster Grenade (Red)

Overview: The XM664 Star Cluster Grenade is a 40mm pyrotechnic signaling round designed for use with under-barrel grenade launchers (UBGLs) such as the M203, M320, and similar platforms. It is used for battlefield signalling, target marking, and identification, deploying multiple bright red star flares that rise into the air upon launch.

Development & Background: The XM664 was developed as a variant of the M585 Star Cluster, featuring red flares for mission-specific signalling and differentiation from other cluster signals. Upon launch, the grenade ejects five to seven bright red star flares, which ascend to an altitude of approximately 200–250 meters, ignite, and descend slowly. The color-coded signal system helps prevent miscommunication in joint-force operations and complex battlefield environments.

Service & Usage: The XM664 Star Cluster Grenade is primarily used for battlefield coordination, emergency signaling, and aerial target marking. The red star cluster is often employed to indicate danger zones, request support, or serve as a pre-designated signal in military operations. It is part of a series of star cluster grenades, including the M585 (White) and XM663 (Green), providing color-coded options for night operations, friendly unit identification, and signaling across various combat scenarios.