Developed in Phase I of the ACR program, the 5×44mm cartridge is of a telescoped configuration, meaning that the projectile is embedded within the casing, surrounded by the propellant. There were prototype rounds of various formats;
- A composite of brass and plastic
The internal structure of the cartridge featured a three-part plastic sabot, which sheathed the projectile, holding it in place. It is later succeeded by the 5×54mm ARES round, also of a telescoped configuration.