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Weapon Name- MAC Cannon (Magnetic Assisted Cannon)
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 with Magnetic Assistance
Range- Unverified
Accuracy- 2.05 MOA
Accessories- N/A
Quick switch firing mechanism- N/A
Scope/Sights- Internal Monitor
Muzzle Velocity- 1810 m/s with Uranium Penetrator, 2310 m/s with Uranium Penetrator and Magnetic Assistance
Firing System- M256 120mm Gun
Miscellaneous/electronic information- Identical to the Rheinmetall 120 mm gun, with additional railgun assistance.








The weapon is more or less the Rheinmetall 120 mm gun, with an added element of electromagnetic assistance, in the form of a railgun. The weapon can use all the same ammunition as the M256, such as the M829, in addition to specialized ammunition designed specifically to make contact with the barrel, and receive the benefit of the railgun. The railgun is compatible with all forms of 120mm ammunition available to the M256, such as the M830 high explosive rounds and the LAHAT laser guided missile, but it can also utilize specialized rounds designed specifically for the railgun. The rounds intended to be used with the Railgun are basically identical to the 9 kilogram M829A2 projectile and sabot in shape, size, and application. Depleted uranium is paramagnetic, and thus ideally suited for use in a railgun. The cartridge possesses very little residual magnetism, and thus loses and gains a charge rapidly. This makes it ideal for being accelerated by a railgun, which requires quick alternation between currents and magnetism in order to be propelled by the barrel. It lacks plastic fins, however, and instead makes direct contact with the barrel, which speeds up the barrel's rate of degradation. In general, the higher velocity of the cartridge is a difficult and complicated aspect of the weapon to replicate, which provides less utility than standard high explosive weapons, such as with the 155mm Howitzer, or even 120mm cartridges. It's main purpose is for it's ability to defeat heavy armor, worn by the heaviest of armored vehicles, and reactive armor, making it reserved primarily for "tank busting", or "bunker busting". It does however have a substantially longer range than a standard 120mm cartridge, which can make it useful for alternative roles in niche applications. The railgun more than doubles the standard M829's energy, from 12.7 million to 25.4 million, which also consequently is what doubles it's range. The maximum effective range of the weapon is 6000 meters, roughly double the range of the standard M829, or 3000 meters.

A Railgun is an electrically powered electromagnetic projectile launcher based on similar principles to the homopolar motor. A railgun comprises a pair of parallel conducting rails, along which a sliding armature is accelerated by the electromagnetic effects of a current that flows down one rail, into the armature and then back along the other rail. Railguns are being researched as a weapon with a projectile that would use neither explosives nor propellant, but rather rely on electromagnetic forces to achieve a very high kinetic energy. While current kinetic energy penetrators such as an armour-piercing fin-stabilized discarding-sabot can achieve a muzzle velocity on the order of Mach 5, railguns can potentially exceed Mach 10, and thus far exceed conventionally delivered munitions in range and destructive force, with the absence of explosives to store and handle as an additional advantage. Railguns have long existed as experimental technology but the mass, size and cost of the required power supplies have prevented railguns from becoming practical military weapons. However, in recent years, significant efforts have been made towards their development as feasible military technology. For example, in the late 2000s, the U.S. Navy tested a railgun that accelerates a 3.2 kg (7 pound) projectile to hypersonic velocities of approximately 2.4 kilometres per second (8,600 km/h), about Mach 7. They gave the project the Latin motto "Velocitas Eradico", Latin for "I, [who am] speed, eradicate" (in the vernacular usage, "Speed Kills".) While the railgun does not achieve the highest velocity possible with modern railguns, it does achieve the 2.4 km/s energy level, which makes it's level of energy exceed what is possible from chemical explosives, making the solid kinetic energy penetrator possess more energy, kilogram per kilogram, at those velocities, than most high explosives, such as TNT. Unlike conventional cannons, railguns do not make use of explosives to deliver high energy projectiles to the target, such as C-4, or TNT, and instead rely on the heavy mass and high velocity of the targets to deliver their energy. TNT possesses approximately 4.18 megajoules of energy per kilogram, while the railgun possesses 5.76 megajoules at a velocity of 2400 m/s.

Railguns make extensive use of electrical energy, and due to the fact that electric energy storage is generally less efficient in terms of overall mass compared to hydrocarbons or other contemporary fuels, any railgun system will add considerable weight to the vehicle. Railgun efficiency can be surprisingly high, with army reports suggesting a roughly 40% electricity to mechanical energy conversion efficiency, or breech energy to muzzle energy levels. (Page 9) Regardless, this already requires 2.5 times the energy that the muzzle energy of the weapon would suggest, more than doubling the energy requirements to reach the desired muzzle velocity. Capacitors are necessary for the use of railguns; the ability to dump large volumes of electricity in incredibly short amount of times is paramount to their high velocities and rapid energy transference, which needs to take place in fractions of a second, to be useful. High grade lithium ion capacitors can store approximately 14 watt-hours per kilogram, or approximately 50,000 joules. Comparatively, a single kilogram of diesel fuel can store 46 million joules, or 920 times the amount of energy. While capacitors generally have less energy storage capacities than batteries (approximately 1/20th the amount as lithium ion), and can only store their energy for a matter of minutes or hours before draining, they have comparatively longer cycle lives than batteries, being capable of millions of uses before degradation. This implies that, for the MAC Cannon to double the energy of the 120mm cartridge, or create 12.7 million joules of energy, it would require 12.7 million / 50,000 kilograms of lithium ion capacitors, or approximately 254 kilograms. Given the inefficient nature of railguns, this is approximately 635 kilograms, per shot.

Realistically, it is much higher than this. To allow for multiple, sustained shots, multiple groups of capacitors would be needed, for instance to allow for 3 shots in rapid succession, you would need 3 clusters of capacitors, or, 3 x 635 kilograms of weight. For practical considerations, charging capacitors up to 90% of their full capacity is generally considered unreasonable. A level of 10% variation would be required, or, an additional 10% of weight for each cluster. Capacitor's make poor long term storage devices; compared to lithium ion batteries, which dump their energy approximately 8% per month (so, a battery loses 8% of it's charge per month), it instead loses approximately 1-2% per minute. Capacitors make incredibly poor long term storage devices, making a railgun's capacitors merely temporarily holding devices for energy, so that the battery isn't burnt out and destroyed from the rapid energy discharge, This requires the capacitors to "charge" before each shot, the time of which can depend on the power source, itself. This means another 10% increase in weight for the battery/capacitor combo, as batteries are needed to charge the capacitor's. Utilizing a hybrid engine, some of the energy can be sapped from the vehicles main battery to power the capacitor's. In fact, the gasoline/petrol/diesel conversion to electricity itself can allow for a much more efficient fuel, or use of a fuel with a much higher energy density. Diesel fuel possess approximately 920 times the energy as a capacitor, and approximately 90 times more than a standard lithium ion battery, which makes it a much more ideal way of transporting the energy over long distances. In effect, the vehicle's own engine and fuel supply can be used to power the cannon's. Regardless, for each shot, the vehicle will require approximately 635 additional kilograms added to the vehicle's weight in lithium ion capacitance, or, 1400 pounds. This is .7 tons.

The rate of the fire of the vehicle depends on a number of factors, but primarily this is the horsepower of the engine and it's conversion rate into electricity, the amount of electrical storage in the batteries and the amount of capacitance, and the heat and recoil tolerance of the vehicle. Standard arrays utilize approximately 4 "cells" or "clusters" of capacitors, which weigh approximately 2.8 tons. This allows for 4 repeated shots, theoretically within seconds of each other, although for practical purposes (such as heat dissipation and recoil of the vehicle, as well as target acquisition), is generally much slower. After these capacitors have discharged their temporary energy, the rate of fire depends on the rate of recharge. Initially, this relies on the amount of electrical energy storage by conventional means, or batteries; this requires approximately 26 kilograms of lithium ion, at approximately .5 a megajoule of energy storage per kilo (although certain batteries can get up tp even 1 megajoule of energy per kilo). While the rate varies, for vehicles that generally require quick charging and discharging, this is approximately 1500 watts per kilogram, or 1500 joules per second, per kilogram. This requires approximately 1075 kilograms of lithium ion per 20 seconds it takes to charge each capacitor (or, 31.75 million joules /1500, /20). Because the tank's battery is several tons, it is generally much faster than this, but practical rates of fire are generally limited to 1 round every 10 seconds, until it is discharged. After this, the amount of energy that can be produced depends highly on the engine itself, or how much power it can produce. With a standard 1500 horsepower engine (such as the one present in the M1 Abrams of the German Leopard 2), this is approximately 1100 kilowatts per second, or 1.1 million joules per second. To reach the required 31.75 million joules, it takes roughly 29 seconds, with the engine at full drive. To reach these levels of power, the vehicle needs to be stationary, and at it's maximum power output, which it rarely is, for efficiency reasons. This relegates the realistic, long term rate of power, to 1 round per minute. It takes around .69 gallons of gasoline per shot, in terms of energy, for each shot. When conversion of gasoline to electricity is considered, this is more like .83.

The handle these stresses, the barrel is also largely made out of depleted uranium, being significantly heavier than the standard steel barrel, at 6175 pounds instead of 2600, increasing the weight of the over-all system by 3575 pounds, decreasing recoil somewhat, but also being more heat and erosion resistant, and more importantly paramagnetic, as it absorbs magnetism but does not maintain residual magnetism. This material is similar in composition to the depleted uranium round.

Another added benefit of the increased energy, for the most part, roughly doubles the range. Because the round is fired at an angle, even though the velocity only increases by the square root of 2 even with double the energy (I.E. 1.414), this gives the round roughly double the range, based on it's ballistic trajectory. As well, importantly, at the same range it has roughly double the energy, allowing it to defeat tank armor that was otherwise resistant to such rounds (such as the abrams), and ensure the destruction of the target material. This puts the velocity of the round at roughly 2400 m/s. The barrel life is slightly reduced at this velocity, to roughly 200 rounds per barrel, compared to 300 for regular cartridges. With improved guidance and calculation systems, this increased velocity allows the weapon to easily extend it's range beyond the generally accepted maximum effective range of 3000 meters, to 6000 meters. All in all, the round possess roughly 12.7 million joules with a roughly 9 kilogram round traveling at around 1680 m/s. With the magnetic assistance, the round is capable of producing roughly 25.4 million joules, or roughly double the energy.