Summary
Magnetic Accelerator Cannons are a type of powerful weapon system employed by the United Nations Space Command military forces. Also known as Mass Accelerator Cannons, they are coilguns which work by accelerating ultra-dense projectiles (usually made of tungsten or depleted uranium) to extremely high velocities via a linear motor consisting of powerful magnetic coils. These weapons rely on the sheer kinetic energy of the projectiles they fire in order to do damage. The technology is applied on various scales - from small vehicle mounted ones capable of destroying light armored vehicles to multiple kilometer long monstrosities which fire 3,000 tonne projectiles as a small fraction of the speed of light. MAC guns are most famously used as the primary armament on the frigates and cruisers of the UNSC Navy - which fire 600 tonne projectiles at velocities of up to 30 km/s.
Powers and Stats
Tier: 9-A | 7-C | 6-C
Key: M68 Gauss Cannon | Cruiser/Frigate MAC | Super MAC
Name: M68 Asynchronous Linear-Induction Motor, Gauss Cannon, Magnetic Accelerator Cannon, Mass Accelerator Cannon
Origin: Halo
Age: At least a few decades (common tech by the time the Covenant first appeared)
Classification: Railgun/Coilgun
Wielders: UNSC Army, Navy, Air Force, Spartan Program
Attack Potency: Small Building level (Fires a 25x130 mm projectile at 13.7 km/s. Assuming it is made of tungsten, it would have a kinetic energy of over 115 megajoules) | Town level+ (Fires a 600 tonne projectile at 30 km/s with kinetic energy of roughly 270 Terajoules) | Island level+ (Fires a 3,000 tonne projectile at 0.04c with kinetic energy of roughly 216 Exajoules)
Speed: High Hypersonic (13.7km/s) | High Hypersonic+ (30 km/s) | Sub-Relativistic (0.04c)
Durability: Unknown
Range: At least a 8 km | At least 3,000 km (The Commonwealth, a UNSC frigate, managed to hit a target at such range with her main MAC during the Battle of Chi Ceti) | Much greater
Weaknesses: Very loud and can potentially cause severe hearing damage to anyone within 20 meters if they do not have some form of protection, low rate of fire | Low rate of fire, needs an AI or tactical computer as human gunners cannot make the necessary calculations and adjustments quick enough, often fired at reduced power settings (sacrificing sheer kinetic energy for greater recharge rate and fire rate) | Suffers from the same weaknesses as the frigate/cruiser MAC
Feats: Can blast apart Scorpion Tanks and Wraiths with a few well-placed shots | Can deplete the shields of a Covenant cruiser or smaller warship with a few shots or potentially cripple an unshielded one with a single well placed round | Can deplete the shields of a CAS-class Assault Carrier with a single shot on a small percentage of its peak power setting or outright destroy a fully shielded CAS-class with a single shot on the highest power setting. Shots in atmosphere can generate shockwaves powerful enough to knock away several hundred meter long ships which are within a couple of kilometers of the projectile's flight path. Projectile can carve out several mile wide terrestrial craters on impact.