The Heat-Discarding Mediums are not ammunition in a traditional sense but rather they are a variety of heatsinks packed into the formfactor of traditional munitions, meaning these heat-management mediums are usually fed through a weapon in methods similar to more traditional munitions – sapping heat away from the main assembly, usually of energy-based weapons, before being ejected.
This makes them particularly useful for weaponry designed to be used in space, seeing as there is no atmosphere the heat could be vented into. It went into production in early YE 41 once Juno “Arsenal” Aurion finished up her design and submitted it to Ketsurui Zaibatsu for scrutiny and production, they are little more than chunks of graphene designed to efficiently sap heat so are extremely cheap and easy to produce which is usually a direct contrast to the weapons they tend to be fitted in.
Statistical information about this ammunition: