Magnetic Accelerator Cannon (Earth-2042)

The Magnetic Accelerator Cannon (MAC), also known as the Mass Accelerator Cannon, is a weapon system employed by the Galactic Empire and its predecessor, the Galactic Republic, on its warships and orbital defense platforms. Essentially large coilguns, MACs serve as the primary armament of the Imperial Navy and formerly Systems Alliance warships and weapon platforms.

Source

 * https://www.halopedia.org/Magnetic_Accelerator_Cannon