The MA2B Individual Combat Weapon System (MA2B ICWS) is an older model of carbine built for the UNSCMarine Corps and Navy. A rare and obscure weapon even within the UNSC's Special Forces, the MA2B is designed to provide superior subsonic capabilities without the bulk exhibited by other rifles at the time. It is short and light, with three P/N 16309 attachment rails to allow it to be rapidly-reconfigured to mission needs. Unlike its close relatives, the MA2B is chambered with the unique M94 9.9mm cartridge rather than the more common M118 7.62mm round, which gives it improved stopping power, range, and accuracy when compared to other firearms issued for covert operations.
The MA5B Carbine was an old weapon, and it was developed according to the needs of Project ORION in the early Twenty-Fourth Century. Riding high on promising results of animal testing, the Colonial Military Administration's research and development division and the Office of Naval Intelligence began to experiment on the concept of augmented supersoldiers. As the program progressed and predictions became more and more optimistic, the CMA saw an opportunity to upgrade their arsenal to include larger-calibre rifles, as they believed that the final operatives could easily withstand the abuse that such a weapon would have. As they already had a new service rifle being designed for their troops, the organisation issued a contract for a subsonic carbine to Misriah Armoury in 2318.
Misriah immediately set to work on designing and testing a new range of larger rounds, with each being assessed based on their power, accuracy, weight, and stealth qualities. To assist with the task, the company worked closely with personnel involved in Project ORION, including potential test subjects. Their feedback informed Misriah that their 9.9x65mm cartridge was the most popular, although complaints with its recoil caused them to reduce it to the M94's final length of 46mm.