Magnetic Accelerator Cannon



"That MAC gun can put a round clean through a Covenant capital ship."

- Sergeant Johnson, talking to Master Chief on board the Orbital Defense Platform Cairo.

The Magnetic Accelerator Cannon, also known as Mass Accelerator cannon, or the Dr. Bressler , MAC gun or MAC cannon, is a large coilgun that serves as the primary offensive weapon for UNSC warships.

A larger variant is in service aboard Orbital Defense Platforms. Within the UNSC arsenal, only nuclear ordnance exceeds the power of the MAC. The M68 Gauss Cannon used by UNSC ground forces may be regarded as a relative of the MAC, albeit on a much smaller scale.

Mounting
The size of a Magnetic Accelerator Cannon is such that it is normally an integral component of a warship's structure. Some types of Defense Stations are literally built around the massive weapon for orbital defense.

Ammunition
A MAC typically fires slugs of either ferric tungsten or depleted uranium slugs at a fraction of the speed of light. The high muzzle speed gives the slug the kinetic energy and momentum necessary to damage a target and partially mitigates the unguided nature of the slug and its lack of maneuverability.


 * The Super MAC Slug can be seen on the level Cairo Station; Go out of the elevator to the bomb and immediately turn left, then go into the hollow rail in the middle of the room, you will see the 3000 Ton Slug being placed into the firing chamber. In other words, stare down the moving thing in the middle of the room. consequently walking into the firing chamber will result in the Master Chief being fired out the MAC gun, and his death.

Aiming
The integration of the MAC to its hull means the entire warship or station must maneuver to aim the weapon. Even with an AI aiming the gun, the required precision and the 'dumb' nature of the ordnance fired means that hitting an evading target at 100,000 kilometers is extremely unlikely.

Firing
The firing process of a super mac gun can be seen in the level Cairo Station. A large outer device climbs up the outside of the barrel. When it reaches the top, vents open on the side of the barrel. The outer device slams down. Fire comes out of the vents and the MAC round explodes out. The process then repeats.

Standard Magnetic Accelerator Cannon
The standard ship-mounted MAC fires a 600-ton ferric-tungsten projectile with a depleted uranium core at 30,000 km/s (this is circa 2525 - MAC technology might have improved since). The large amount of energy needed to fire the weapon is particularly onerous on a warship, and the extended recharge time is a significant factor in combat against Covenant warships as multiple MAC rounds are required to penetrate Covenant shields. The standard MAC is sufficient to destroy any human vessel or severely damage an unshielded Covenant vessel.

The yield of a standard, ship-based MAC, is roughly 58,556 megatons (a standard thermonuclear missile has a yield of roughly 20-30 megatons). This amount of energy is sufficient to vaporize roughly 192 billion tons of nickel-iron.

The energy from a single shot, if all converted to heat, would have a 100% fatality radius of 102 km, and a 3rd degree burn radius of 1051 km.

The has been seen using its MAC cannon as a kind of orbital bombardment, firing 6 rounds within 9 seconds at a Scarab tank from orbit. However judging by the fast rate of fire, and the fact that two direct hits were required to down the Scarab, the Spirit of Fire's cannon may either be a variant that sacrifices power for a fast fire rate, uses smaller slugs, is a special version for orbital bombardments or is an earlier, weaker version of MAC. While the MAC shells appear to cause little damage to the ground, it has been calculated that a 600 ton slug moving at a fraction of light speed would actually be able to breach the crust of a planet.

An experimental version of the MAC was developed to fire three successive rounds on a single capacitor charge. A prototype was mounted on the.



"Super" Magnetic Accelerator Cannon

 * Main article: Orbital Defense Platform

A UNSC Defense Platform typically mounts a much larger and more powerful version of the standard MAC, nicknamed "Super MAC" or "the Big Stick." These Super MACs fired a 3000-ton ferric-tungsten round at 0.4 c ., powerful enough to penetrate a fully shielded Covenant warship and destroy it. By receiving power from ground-based powerplants, orbital platforms could achieve recharge and reload times as short as five seconds.

Given that the ODP fires a projectile at .4c, and the slug has a mass of 3000 tons, we can calculate that the energy expelled is 5,306 gigatons (a standard nuclear warhead is about .03 gigatons). This energy is sufficient to vaporize roughly 3 trillion tons of Nickel-Iron.

Other MAC Sizes
Although never explicitly elaborated upon, there may be many more different sizes of MAC based on the sizes of possible mounts. For example, one might extrapolate that a frigate would mount a smaller, less powerful cannon than a supercarrier or a, if only for power management issues. Conceivably, a 'large' ship could mount many 'small' MACs. However, the lack of such occurrences might suggest that the power of a MAC, once the mass and volume of all attendant components (ex. capacitors) are accounted for, does not scale linearly. (there is one known exception, destroyers are outfitted with two MAC cannons, along with 2 meters of titanium battle plate, the downside is the lack of single ships).

MAC Location
Many believe that the MAC barrel is located near the underside of the ship, where there are three large plates. However, it is more likely that the barrel is located along the entire length of the ship. Logically, the multiple powerful magnets needed to accelerate a 600 ton slug to 0.1c requires an exceptionally long barrel, allowing for many magnets to affect the projectile. The huge 1.17 km length of the Pillar of Autumn would facilitate this, making the most likely muzzle location of the MAC barrel to be located at the protrusion at the ship's bow.

Space Stations MAC Location
Further supporting the hypothesis of a barrel running through the entire ship is the structure and design of Cairo Station. After exiting the cargo elevator, the player can look up and observe the Super MAC platform in action. The slug travels the entire length of the tower, and exits at the "top." Later in the level, the player can notice the loading zone of the slugs at the base of the firing chamber.