ARH-101 Intelligent Assault Weapon System
NFPA Primary Rifle
ARH-101 in a rare use by an unarmored soldier.
Type Heavy assault rifle
Place of origin New Free Planets Alliance
Service history
In service 2002-present
Used by Free Planets Ground Force
Free Planets Marine Corps
Wars Reaper-Omega War
Heroin Civil War
Scrin War
Marsalian Civil War
Alliance-Russia War
Viertianan Scramble
Ineran War of Liberation
Cambrian Civil War
Chousin War
Drakan Wars
Killik War
Production history
Designer Rokkenjima Island Arsenal
Designed 1998-2001
Manufacturer National Defense Firearms Manufactory
Specifications (ARH-101)
Weight 10.5 kilograms
Length 1,200 millimeters (maximum length); 800 millimeters (minimum length)
Barrel length 700 millimeters (maximum length); (300 millimeters (minimum length)

Cartridge 8.36x70mm FPDF
Cartridge weight 18 grams
Caliber 8.36 mm
Action Electrically-operated; push-through feed-and-ejection; swinging chamber
Rate of fire Variable; up to 700 rounds/min (rpm)
Muzzle velocity Variable; up to 2,000 m/s
Effective range 4,400 meters
Maximum range 6,000 meters
Feed system 40-round detachable box magazine; 150 round detachable box magazine; disintegrating belt feet
Sights Variable
"A heavy son-of-a-bitch to be sure, but I'll be damned if there's a shot she can't make!"
―Private Ean Juan, Ground Force infantryman

The ARH-101 Intelligent Assault Weapon System is an assault rifle that functions as the standard service rifle for the Free Planets Ground Forces. Developed by Rokkenjima Island Arsenal under contract to the Free Planets Defense Force, it was designed to replace the lighter and more compact ARL-100 Modular Assault Weapon System originally produced for the Marine Corps. Firing the heavy 8.36x70mm FPDF round at extremely high velocity, the weapon is renowned for its tremendous size and weight, being similar to a light machine gun in both categories. Its large size and weight are a function of its intended purpose as a replacement for the standard assault rifle, marksman rifle, and light machine guns normally allocated to infantry units, and its use by power armor-equipped infantry.

Slowly phased into use over the course of several years, the ARH-101 is now the universal service rifle of Ground Forces infantrymen, replacing a myriad of other weapons previously in service to cover the roles it now covers. It has thus far served in every Ground Force engagement since its introduction in 2002 C.E. Interestingly, due to its heft, it is never used as a parade rifle, with infantrymen switching back to the smaller ARL-100 for parade duty.



The ARL-100 that the ARH-101 replaced.

The first assault rifle designed for the Defense Force was the ARL-100, a lightweight bullpup weapon of similar size and function to 21st century Earth assault rifles. Firing a 5.72x35mm round at high velocity, the ARL-100 was well-suited to taking down lightly armored targets, but the lightness of the 5.72x35mm round resulted in poor performance at long range and an inability to cause significant wounds through heavy body armor. As infantry power armor technology began to develop, some of the primary advantages of the ARL-100, its light weight and low recoil became less important, since power armor offered to amplify the average infantryman's strength to be able to effectively control a much larger weapon.

As such, the Ground Forces began soliciting bids for a new weapon, to be presented in a competition format. The new weapon was to utilize the 8.36x70mm machine gun cartridge for improved ballistics and stopping power, and was to provide accurate fire to a minimum range of 2,000 meters. Although size and weight were not of much concern for the average infantryman wearing power armor, size was not to exceed 1,200 mm and weight was not to exceed 12 kilograms, in order to allow the weapon to be considered compatible with the existing light machine gun logistics network and to prevent transport issues. Several companies, including Halk Armory, Rokkenjima Island Arsenal, Tyrola Small Arms, and Nasha Personal Defense Systems submitted bids to the competition.

XASR-101 projectEdit

Dubbed the XASR-101 project, the competition pitted the entrant designs against each other in a series of tests that lasted more than two months. All of the entrants used electrically-primed ammunition and had integrated fire control computers to help gauge distance, wind factors, and at extreme ranges, the Coriolis effect. The designs from Halk Armory and Tyrola Small Arms were relatively simple designs, possessing many of the hallmarks of standard rifle design and with fixed barrels lengthened to what was considered an optimum balance between the competition maximum of 1,200 millimeters and the minimum required for accurate long-range shots. The Tyrola design incorporated a helical magazine in a bullpup configuration, giving it the highest round count with a standard magazine as well as the smallest design, while the Halk Armory design was a conventional rifle with a box magazine. Both were designed mostly for unarmored use, and were designed with a relatively low rate of automatic fire plus a reduced muzzle velocity to make them more controllable. Nasha Personal Defense Systems' design was itself reminiscent of a light machine gun, with a long barrel coming in just below the competition maximum for long-range fire and standard weight-reducing fluting, although modified with a bullpup design to reduce overall length. It also incorporated a quick-change barrel mechanism, another feature common in light machine guns, to allow for changes in barrel length as needed for a given operation, reducing the gun's overall length significantly.

NFPA Rifle2

Rokkenjima prototype design tested in the unarmored competition.

The Rokkenjima Arsenal design, however, was an utter beast of a weapon. At maximum length, it hit the very edge of the competition maximum, reaching 1,200 millimeters exactly, and coming in at just 1.5 kilograms below the maximum weight. Like the Nasha Personal Defense Systems design, it was capable of quickly changing its barrel length, but did so on its own through the use of mechanically added and removed barrel extensions added to both sides of the barrel. The varying combinations of extensions allowed the barrel to be lengthened in 100 millimeter increments from 300 mm to 700 mm, with the longest barrel just reaching the maximum allowed rifle length. Mechanically-active systems abounded throughout the gun, including active recoil springs to dampen the force of firing to an automatic magazine ejection system. The design stirred a major debate among the Ground Force acquisition command as some claimed it was excessively large and heavy, while others claimed power armor could overcome the disadvantages associated with such a heavy gun. Both the Nasha and Rokkenjima designs were designed for armored use, and thus had no restrictions on rate of fire or muzzle velocity, resulting in extremely high recoil and a much heavier gun overall.

The competition tested all entrants in a series of tests in both standard field uniforms and the experimental XHEM-05 infantry powered exoskeleton. The Tyrola and Halk designs received high marks in the field uniform category for their relative ease of use, comparatively controllable recoil, and relatively compact size, while the Nasha and Rokkenjima designs fared poorly for their huge size and cumbersome scaling for the normal infantryman. The results were switched however for the power armor test, with the Tyrola and Halk designs receiving low marks for lessened stopping power due to rate-of-fire and muzzle velocity restrictions made in order to make the weapons usable by unarmored soldiers, while the Nasha and Rokkenjima designs received praise for their adaptability and power. With such different test results, it was quickly realized that the deciding factor would not be the guns themselves but the Ground Forces' pending decision on whether to adopt power armor as standard infantry equipment. Previously, the Ground Force had favored standard field uniforms or lightweight armored vacuum suits rather than a true powered armor suit, but advances in the fields of mechanical engineering had created technology that delivered sufficient mobility and flexibility to replicate the movement range of the human body, making power armor a viable alternative. If power armor were adopted, it would strongly favor the Nasha and Rokkenjima designs, but if it was rejected, Halk or Tyrola would be the leading designers.

In the end, after a division-scale war game between forces equipped with standard uniforms and power armor, it was decided to adopt the new armor, pushing the Nasha and Rokkenjima offerings into the finals. In a final one-week competition, the Rokkenjima design emerged victorious, having survived the reliability tests which were considered to be the greatest challenge for a weapon with so many active parts. The greater flexibility offered by the variable barrel made the weapon more accurate at long range and also more compact when moving in confined spaces, a capability the Nasha design could not match.

Introduction to serviceEdit

The Rokkenjima XASR-101 design entered a phase of more intensive testing to further refine the weapon, now that the XHEM-05 powered exoskeleton was also reaching the final stages of introduction. The fire control and barrel maintenance computers, formerly separate, were merged into a master control computer to make repairs easier in the event of a breakdown. A mechanical backup to the normally electrically-fired weapon was added, and the barrel extensions modified to achieve a tighter seal and reduce susceptibility to dirt and dust. The automatic magazine ejection system was abandoned and instead the magazine catch was moved to a more ergonomic position, and the gun was modified to accept a direct uplink either to an operator's cyberbrain or power armor to better interface with its targeting systems.

Upon entering service, the gun was reclassified as the ARH-101, requiring the creation of an entire new class of weapon in the inventory system. Previously, both the ARL-100 had been designated the ASR-100, as the Defense Force only maintained a single assault rifle classification. The XASR-100 was so different from its predecessor however that it warranted the creation of a new class, the heavy assault rifle, giving the designation ARH. The ASR-100 was reclassified as a light assault rifle, reentering the inventor as the ARL-100. The weapon was phased in over the course of two years, first to forward-deployed infantry units on Earth, then to garrison units in the Alliance homeland. The rifle has been partially adopted by the Marine Corps for use in field battles, but for shipboard combat, the ARL-100 is still used alongside the ARH-101.

The weapon as issued to most infantrymen is equipped with a bipod, 40-round box magazines, and a digital scope designed to be linked to a helmet feed but also capable of directly displaying imagery like a normal scope and acting as a camera for blindfiring. Soldiers have been known to add their own accessories to the weapon, which is capable of accepting an underbarrel grenade launcher in place of the bipod, as well as other accessories.


The ARH-101 is constructed primarily of a titanium frame, chosen for its inherent toughness over aluminum, which is lower-weight. Furnishings are made of composites to save weight and reduce vulnerability to corrosion. The barrel, bolt, and bolt carrier are machined from the same Arzorium-Alium alloy used in the production of ship armor to provide a long barrel life and good heat absorption and dissipation properties. It is estimated that a switch to lighter-weight steel for the barrel assembly and aluminum for the frame could save 1.5 kilograms from the design weight, but the tradeoff in durability was determined to not be worth the switch and the current material composition remains in place. The barrel uses ten-sided polygonal rifling to maximize muzzle velocity and efficiency while maintaining accuracy at long range.


The LSAT light machine gun pioneered the swinging chamber action used in the ARH-101.

The firing mechanism is electrically actuated under normal operation, although a gas block system exists. In normal operation, the gas block is sealed to prevent any return of the exhaust gases to the firing assembly, but for mechanical operation of the gun this gas block can be opened to provide the force needed to reload the weapon after each shot for automatic fire. The electric firing mechanism cycles the bolt using motors and ignites the gel propellant in the disintegrating shell casing to fire the weapon, making the design a "semi-caseless" firearm. The electric firing mechanism was adopted to increase flexibility, as the rate of fire can be dialed up and down depending on desired function, something that is not possible with a fixed mechanical operation. Mechanical operation is locked at an automatic rate of fire of 400 rounds per minute, while the electric mechanism can vary between semi-automatic to 700 rounds per minute. The mechanism can also under-ignite the propellant with a smaller electrical charge than normal to reduce the muzzle velocity. At low muzzle velocity and low rate of fire settings, the weapon is marginally controllable by an unarmored infantryman, although the weapon's sheer bulk makes firing it from anything but a prone position a difficult prospect.

Both the electric and mechanical operation systems utilize a swinging bolt, based on technology developed in the early 21st century. Compared to traditional rotating, closed, or open bolt systems, the swinging bolt is much simpler in mechanical complexity, partially making up for the more complicated electrical firing system. It also provides more reliable round extraction and feeding, while insulating the chamber from barrel heat. The weapon is designed to fire standard semi-caseless rounds with a gel propellant and disintegrating casing, but is capable of firing traditional powder ammunition if set to mechanical operation. Since 8.36x70mm rounds are only commonly used by the Defense Force, and all Defense Force rounds are issued with gel propellant, however, it is unlikely that any powder-fueled rounds are to be found.

Regulation of the gun's status and firing is achieved by the master control computer. The computer is linked to the integrated targeting system attached to the gun as well as the operator's armor and is responsible for adjusting the barrel length, muzzle velocity, and rate of fire to best engage a given threat. It is also responsible for alerting the user in the event of a jam or other malfunction and uploading the current target into the round computer for long-range fire where smart ammunition is required. It is also equipped with a bayonet lug although bayonets are not commonly issued to field infantry.


Bullets NFPA

Several 21st century bullets, demonstrating the differences in ammunition type

Unlike its predecessor, the ARL-100, the ARH-101 is designed to fulfill a multitude of roles, from standard sniper rifle to assault rifle and light machine gun within a standard infantry squad. For use as an assault rifle, it is programmed to fire at a moderate velocity of approximately 1,400 m/s to sustain a high rate of fire from a standing position. In this way it trades range and accuracy for rate of fire and controllability. Barrel length is also usually set to approximately 500 millimeters, although it can be increased or decreased depending on need. As a light machine gun, the weapon pushes its rate of fire, muzzle velocity, and barrel length to the maximum allowable settings, but is designed for prone firing while anchored with a bipod to keep controllability within reasonable bounds and trading per-shot accuracy for range and rate of fire. As a marksman's rifle, rate of fire is minimized to semi-automatic only, and muzzle velocity and barrel length are moved to their maximum settings for the best possible range without multiple-shot disruption for the shooter.

To maximize efficiency in these roles, the weapon is also equipped to take multiple types of ammunition. Standard rifle ammunition is a copper-jacketed round with a tungsten carbide core for maximum penetration of armored targets, relying on the bullet's tremendous kinetic energy to inflict damage on lighter targets. This ammunition is considered suitable for use out to 1,800 meters, making it acceptable as sniper ammunition in most cases. With this ammunition, the ARH-101 can penetrate standard body armor and even light bulletproof glass out to 1,000 meters, although modern power armor and shielding units can give a degree of protection against the round.

For long-range engagements, guided ammunition is used. These rounds replace part of the standard core with a microcomputer and adjust ballistic ridges along the bullet's surface to guide the round in flight. While not guaranteeing a hit against concealed targets, and unable to steer the bullet around intervening obstacles, it allows the bullet a much greater chance to hit at ranges beyond 1,500 meters, where bullet flight time begins to become a factor. Information is uploaded into the bullet's computer by the master control computer with data from both the onboard targeting sensor and the operator's power armor, and guidance is carried out by the bullet in mid flight to account for wind, temperature, and other variables that may become an issue in the space between the shooter and the target.

Against armored targets, a heavier variant of the standard bullet is used, with a larger tungsten carbide core machined to a thinner point for greater penetration. However, as a rifle caliber, the 8.36x70mm ammunition is not capable of penetrating medium-armored vehicles, and 25mm ammunition is used for this purpose instead. Incendiary, tracer, and explosive bullets also exist, but are usually issued or requisitioned for special tasks.

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