Arm Cannon or Marble Cannon is the common name given to the Atlan military’s primary weapon, the Personal Marble Cannon (PMC). PMCs vary in size, shape, and style but all operate according to the same basic principles. Smaller versions of the weapon are wrist and forearm mounted devices with one, two, three, or more barrels pointing forward and situated above the user’s wrist. The devices are designed to shoot small metallic or ceramic balls at high speeds and are capable of causing fatal injuries when necessary. The wrist and arm mounts stabilize the device and hold the ammunition. Larger versions are equipped with six or more barrels that wrap around a user’s hand and are connected to a backpack full of explosive ammunition which is fired at speeds up to 120 rounds per minute.

The PMC weapons are powered by a Magi operator and use compressed air to fire the ammunition anywhere from 20 to 300 feet. PMC weapons are given a numerical designation according to the model and function. The most recent model is known as the PMC-147.

The first marble bombs were little more than a dangerous footnote in the history of fireworks. Marble weapons can trace their origins to 252 PM in the town of White Falls. At the end of each fall walnut harvest passed, one of the laborers would use his free time for his off-season passion—creating and selling fireworks. One evening late in 252, he had a peculiar idea while looking at a half-full bag of walnuts left on his work desk. He filled one-half of an empty walnut shell with the firework gunpowder and then secured the other half to the hollowed husk with a thick resin. After drilling a tiny hole in the top of the nut the man stuck a long fuse in the hole. Once outside, the man lit the fuse and threw the nut into the air. Much to his amazement, the nut exploded into a bright fireball.

The man contacted his workmates and told them all to meet him in a nearby park a few days later. Armed with a satchel of nut-bombs, the firework master met his friends on the appointed day. Before they could ask what was going on he began hurling the bombs at their feet where they exploded in a flash of color and sound.

Well amused and completely captivated by the new toy, the small group of men decided to collaborate on creating a marketable product. Though it was nearly 250 years prior to the signing of Atla’s constitution and transcontinental travel was still difficult, fireworks were wildly popular across the continent. The man already had a profitable business selling his wares and knew spending time creating the new toy would no doubt prove a profitable venture.

Over the winter the men spent their time refining the initial design. Changes included replacing the nut casing with a smaller, spherical casing that resembled a playing marble popular at the time. Inside the marble was a set amount of explosives (discovered after trial and error—and burnt fingers).

The following spring at the International Trade Fair the group demoed their new invention. Billed as a “Firework toy for the whole family” the men saw their invention as a gag item and not something that would change the face of warfare forever. Regardless of their lack of foresight, the “Marble Bombs” as they called them, were a huge success.

Within five years of the Marble Bomb’s creation the men formed their own company to manufacture and sell the bombs. Another five years into their venture and the military of Westlake purchased the rights to the bombs for what would be 100 million dollars in today’s money.

Once the military purchased the rights to the Marble Bombs the fate of the ‘toy’ changed. Instead of the colorful concoction of gunpowder, the engineers filled the bombs with a volatile and more explosive mixture of high explosives. The once protective and rigid outer case (almost as hard as a marble, partially giving the toy its name) was replaced with something more pliable and fragile. Finally, the single most deadly change to the bomb, which secured its place in the military’s arsenal, was the removal of the fuse. By making the mixture inside the marble more explosive and volatile users could hurl the marbles at a target where they would explode on contact. As valuable as they were, the infant weapons were so dangerous that 1 in 100 users would lose a limb or be wounded fatally during training exercises.

Marble Bombs became the weapon of choice across the civilized world almost overnight. The design for the bomb was easy to copy and spread rapidly after the first few engagements in which they were used. Though the combination of explosive materials and casings varied tremendously, the design remained fairly constant.

Accidental deaths and injuries became commonplace once the weapons spread to untrained hands. By now the bombs were destructive enough individually to remove a hand or foot (or in more gruesome examples, explode the head of anyone naive enough to hold hone in their mouth for any period of time). Still packed in the marble sized casing, such a small yet destructive force was almost impossible to transport. Ships carrying thousands of the bombs were sunk when one bomb would accidently detonate during a strong storm, thereby detonating the other bombs. High temperatures would cause weapons storage facilities to explode, nearly leveling the bases or cities in which they were kept. Soldiers in battle would often trip and fall, crushing their satchel of bombs and detonating the entire supply at once. Indeed the weapons were unkind to anyone who made a mistake while using or transporting them.

Because the marble bombs were so dangerous and unpredictable, swords, bows and arrows, shields, and other hand weapons continued to dominate the battlefield long after their creation. The process of phasing out the hand-to-hand weapons took centuries. Refinements were slow in coming and hard to spread. The weapons were used heavily during the War of the World, though not as primary offensive tools but supplementary defensive options. They weren’t usually given to front-line soldiers or recon teams. Instead, military bases used them as long-range deterrents. Even when Atla became a unified nation, the Grand Provincial Councilor saw that the marble weapons could be used only as additions to the military’s arsenal, not as the foundation of it.

By 100EM the Marble Bombs had become more stable which meant they were used in more ways. Naval warships shot head-sized bombs during engagements and huge marble-bomb turrets were installed as defensive weapons in forts. In addition, the Atlan infantry used the standard marble sized bomb in firearm devices. By this time the accidental injury/death rate had dropped to approximately 1 in 20,000 bombs. This number is somewhat misleading though. While the stability of the bomb improved radically, the number of bombs being used in any given engagement had increased even more. This meant that there were in fact, more accidents per given battle or time period, despite the bombs themselves being safer. It is estimated that, since the creation of the weapons, 15,000 Atlans have died as a result of accidents or misuse.

Modern marble bombs are vastly different than their ancient counterparts. Instead of being tossed by hand they are shot out of arm cannons. Infantry Weapons Systems is pioneering advances and changes to the marble bomb faster than any other group. Though they are an independent company, the Grand Provincial Councilor has contracted them to work exclusively for the Atlan military. This contract will last for another ten years at which time the terms can be re-negotiated. Working with IWS has been a major factor in Atla’s military dominance over the past decade. Their latest creation is known as the Personal Marble Cannon 147, or PMC-147 for short. All of IWS’s arm cannons are given a numerical designation beginning with the PMC-1.

From the outside the PMC-147 appears very similar to the other competing marble cannons used throughout the world. However, most of the differences are internal and performance related. The ammunition tubes traveling from the ammunition pack to the hand unit are lighter and more durable and are now routed from the bottom of the ammunition pack. Upon closer inspection one will also find that the ammunition tubes are slightly elastic, giving users of all sizes a comfortable and effective range of motion.

It isn’t what’s on the outside that makes the PMC-147 so revolutionary however. The ammunition pack, a closely guarded secret, sets this marble cannon apart from any others. While exact specifications and materials used in the ammunition pack are highly classified, the basic structure is now widely known. The ammunition pack is a large, solid backpack that contains the volatile payload of marble bombs. Unlike many other ammunition packs, the 147’s doesn’t separate into main chambers to store the ammunition. Instead, it holds each and every marble bomb in a separate chamber, just large enough to accommodate the bomb itself. This addition has been the single most important feature in keeping the Atlan military safe from friendly fire or accidents. Whereas other ammunition packs are susceptible to sudden impacts or drops which would cause the entire ammunitions storage to detonate, the 147’s ammunition pack can withstand the blow from a sledgehammer without damaging the payload.

Another revolutionary feature of the PMC-147 is its rapid-feed technology. Through a combination of turbines, gravity and pressure differences, a well trained infantryman or woman can launch 200 rounds per minutes, nearly double the current record held by the PMC-145 (at 96 rounds per minutes). With what the designers are calling an ‘intelligent’ ammunition pack, the size, shape and location of the marble bomb chambers adjusts and changes dynamically to keep the ammunition distribution equal throughout the pack, while simultaneously preparing the next sequence of rounds. So as a user begins to deplete their ammunition the inside of the pack will actually change shape. The exact method of making the pack change shape is classified, but its basic function is known. Padded poles, slightly thicker than a sewing needle, are locked into tracks surrounding the inner walls of the pack. As the ammunition is depleted, these tracks will slide in all three dimensions, grabbing and securing the marble bombs as they are needed. Primary motion for the poles is a combination of a user’s input, pressure difference and an external power source (usually solar).

The PMC-147 is available only to the Atlan military. Because of IWS’s exclusive contract with the Atlan government no other nation or entity is able to purchase the weapon or any other in the IWS line. Many other nations and factions have made great attempts to copy the 147’s design recently. However, none of them have been nearly as successful.