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Weapon Name- MAC Gun (Magnetic Assisted Cannon), Mk. II
Round Type- 120mm (4.7) Rheinmetall Ammunition
Over-all length- 6.6 meters (7.2 yd), 21.6 feet
Barrel length- 55 calibers (120mm x 55, or 6.6 meters)
Weight- 7,310 lb (3322 Kg)
Rate of Fire- 12 RPM
Feed Mechanism- 1-round internal magazine (Although autoloaders can load each round like it's semiautomatic)
Round Capacity- 1
Effective Range- 8000 meters (5 miles), 16,000 meters (10 miles) with Magnetic Assistance
Range- Unverified
Accuracy- 2.05 MOA
Accessories- N/A
Quick switch firing mechanism- N/A
Scope/Sights- Internal Monitor
Muzzle Velocity- 1,750 m/s with Uranium Penetrator (15.3 million joules), 2000-2,500 m/s (20-32 million joules) with Uranium Penetrator and Magnetic Assistance
Firing System- M256 120mm Gun
Miscellaneous/electronic information- The weapon is basically identical to the Rheinmetall 120 mm gun except for the Magnetic Assistance system, which is based on the DARPA coilgun acceleration system.








The weapon is basically identical to the Rheinmetall 120 mm gun as it's foundation, however it has external modifications utilizing a guass-gun style acceleration system to magnetically accelerate the round to higher velocities. Typically ranges between 30% and 100% improvement to the except for the Magnetic Assistance it provides on specialized Depleted Uranium/iron rounds. The rounds are basically identical to the 8.35 kilogram M829 cartridges in shape, size, and application except for the fact the rounds have a specialized outercoating, and the projectiles themselves are designed to have better characteristics for magnetic acceleration. Being made of uranium they are already ideal for railguns and coilguns, however some alterations need to be made to the projectile to make it more effective in this system. The weapons is typically designed to use M829A3 and M829A4 style cartridges, with the above changes to enhance their performance from a rail gun. The weapon traditionally uses a longer, 55 caliber barrel, longer than the 44 caliber version to give slightly increased power and a longer magnetic rail system. The weapon also almost always used an auto-loader for the gun, but does not have to, with more primitive manually loaded versions available.

The magnetic system operates very simply, being a very base type of rail gun/coil gun hybrid, more closely resembling a gauss gun, and similar to the design used by Darpa to accelerate 120mm mortar rounds. [1][2] The gauss gun is 35% efficient, requiring between 15-45 megajoules of energy per round fired, which is a slightly higher level of efficiency than the Darpa coil gun at 22% efficiency; this is achieved in part by the larger size and higher starting velocity, as well as superior materials, and the projectile material itself being more magnetic. The most innovative feature of the weapon is that it is essentially a hybrid of standard chemical propellant, or gunpowder rounds, and magnetically accelerated weapons, essentially resulting in a magnetically assisted weapon. The design allows standard M829 and other 120mm rounds to be fired, including LAHAT missile or high explosive rounds, while also allowing for more powerful, "Super Charged" electromagnetic rounds to be used sparingly. The weapon is essentially a hybrid guass gun, utilizing a gunpowder chemically accelerated propellant for the base round, and then enhancing the power of this round with the gauss gun magnetic acceleration. This is useful for a number of reasons, which plays off of the weaknesses of both systems of propulsion. Magnetic acceleration systems, while they allow for a high velocity, are limited severely by the size of the railgun or guass gun, and the battery pack needed to fire them. They have slow rates of fire, due to the need to charge the capacitors, and overheating issues that come from their use and high velocity. As a result of their increased price and reduced rate of fie, regular 120mm rounds can be used without any magnetic acceleration, and varying degrees of magnetic acceleration can be used giving the round a variable level of power. This is useful not only to conserve the power of the batteries and capacitors, but prevent over penetration of certain targets, allowing for adjustable rates of power on demand, rather than needing to use different bullets. Given a naturally high injection velocity from the chemically propelled round, they are able to achieve extremely high velocities of up to 2,500 m/s, although ranges between 2,000 and 2,500 are typically used.

Velocity is much harder to increase by chemical propulsion means, with a maximum theoretical velocity up to 2.5 km/s, and maximum realistic velocities being under 2 km/s. The rate of energy transfer is simply not enough enough with chemical propellants to go over these levels, and the recoil and energy backblast are too high to realistically achieve such velocities regardless. Magnetic accelerated projectiles can achieve higher levels of power, and up to 20 km/s velocities, however batteries and capacitors are less efficient than gunpowder, and more complicated to use, requiring cooling systems and protection from the magnetic fields generated by the gun. This makes high energy railguns or gauss guns difficult to create, with few in actual service. By utilizing the chemical propellant to provide a high initial injection velocity for the railgun, this not only allows the use of many different types of rounds, such as high explosive rounds, but also allows for magnetically assisted rounds to be used when desired. When higher rates of fire are needed the tank can use chemical propellants only, and when armor penetration or range is desired (but at lower rates of fire), the magnetic assistance can be used. In this way, the weaknesses of both weapons play off of each other, with variable rates of power for the MAC gun being available. This means that while the capacitors are recharging the MAC gun is not completely useless, and can be used to fire regular rounds, and after the capacitors are charged to fire more powerful rounds. This gives the system the advantages of both weapons, while mitigating most of their disadvantages, and dramatically increased power, sufficient to penetrate the majority of MBT's.

The weapon's capacitor and battery banks are incredibly large and stored internally within the vehicle, to protect them from damage, while the barrel has a protective sleeve over the barrel to protect the magnetic acceleration system from harm. This increases the weight of the barrel substantially, from about 2,620 lb to 7,300, or from 7,300 to 12,500 while in the weapon's mount. With newer barrels the barrel life has been increased to roughly 1500 rounds, although this is greatly shortened with excessive use of the railguns, potentially down to 300 rounds. Given the incredible energy production required, virtually all vehicle's using the weapon must be hybrid electric systems, relying on the powerful engine's to produce enough energy to make the cannons function reliably. With more modern capacitor's and batteries, the weight reduction is decreased, however the price of the battery back goes up substantially, as does the gun itself. As the weapon uses 5 to 16 megajoules per shot, is does not need nearly as much power stored up as a normal guass gun in order to operate, however due to it's 35% efficiency, it needs to store 15-50 megajoules of energy to operate. With lithium-ion capacitors storing up to approximately 11 watt-hours of energy per kilogram, or 40k (40,000) joules per kilogram, thus necessitating approximately 1250 kilograms (2,750 pounds) of capacitors for the storage of 50 million joules of energy (50 megajoules). This allows for approximately 3-4 rounds of 30% assistant rounds to be fired, and 1 round of 100% increase rounds to be shot on a fully charged capacitor bank. The vehicle also utilizes a 300 kilograms of lithium titante batteries, for faster charging of capacitors (about 30 times the discharge rate of lithium ion), and to serve as a stand-off between the primary batteries of the hybrid vehicles and capacitors, as the hybrid batteries are used to charge the lithium titanate batteries, and then the capacitors. The Lithium titante batteries have a rough watt-hour to kilogram ratio of approximately 100, thus providing approximately 108 megajoules of energy storage. Typically the lithium titante batteries are at full charge. The capacitors have a very low discharge rate in comparison to most capacitors and thus can stay charged for several months, however typically they are slightly under charged at all times to reduce energy waste and consumption. Given a 1500 horsepower engine (standard for most tanks), and the fact there are 756 watts per unit of horsepower, a standard tank engine produces approximately 1.134 million joules of energy a second at full power, or can generate enough power to fully recharge the capacitor bank in about 60-75 seconds. However, if the vehicle is moving or running at lower horsepower levels than this, such as 750-1300 horsepower, it obviously will take longer. Typical recharge times for a full capacitor banks in combat conditions are approximately 2-3 minutes, with allows for the engagement of only a few targets in this window. The energy production consumes an entire kilogram of gasoline to operate, or roughly 1/3rd of a gallon. As the engine is only 40-50% efficient, it takes roughly 2/3rds of a gallon of gasoline to actually recharge the capacitor banks and lithium titanate batteries. For short bursts the lithium titanate batteries can recharge the capacitors in about 10-15 seconds, thus allowing for a greatly extended 3 supercharge shots and 10 partial charge shots in about a minute, however afterwards the vehicle resorts back to it's 2-3 minute recharge time.