Authiik Firearms

The authiik small arms industry on Mabatsar thrives as a result of mandatory conscription and militia participation. Each adult authiik owns at least one long arm and are required to log regular range time to ensure proper practice. For examples of historic firearms and ammunition, see "Historic Authiik Firearms".

## Cartridges

Authiik cartridge technology took a similar path to that of humans. A metallic casing filled with combustible powder, a pointed bullet made from a soft metal at the front, and an impact sensitive explosive at the back struck by a firing pin to light the powder. This builds pressure due to the expanding gasses within the casing, which propels the bullet forwards. The cases are often made from aluminum, and bullets are made from cast lead coated with a copper jacket, or 3D printed copper with interior cavities designed to split and shred the target.

The average caliber of an authiik firearm is largely similar to than that of a similar class created for human use. This is due to the physical resilience of the authiik body requiring more energy delivered to the target to cause the same damage. Bullets will either be larger and heavier, or faster relative to the authiik's physical size to compensate and provide more impact force.

### Authiik Military Standard Cartridge Ammunition

The first cartridge types found on the vessels present in the fifth fleet were the eight standard issue military ammunition types discovered alongside one another in their personnel armories. They were assigned foreign ammunition designations sorted by overall length. For example, the short .44 caliber pistol cartridge with a 12 millimeter diameter bullet and a 21 millimeter long case was given the designation "E7-CP2", as it was discovered at the same time as other standard ammunition and was the second longest chemically propelled cartridge of the eight.

This is an acronym for Extraterrestrial 7, Chemical Projectile 2. Extraterrestrial 7, or E7-, was the designation given to the authiik upon first contact. This is due to the fact that the authiik were the seventh sapient alien species that humans had come into contact with. Chemical Projectile is the term for a chemically propelled projectile, whether caseless or non. Other designations would be given such as "ES" for electromagnetic railgun or coilgun slugs, "HC" for hydrogen plasma cells, "CC" for capacitive cells, or laser weapon power sources, and finally "XA" for exotic ammunition, anything that would not otherwise be easily described by the earlier four categories.

#### E7-CT1 (aka 8.5x17mm)

The shortest of authiik standard issue cartridges present on the fifth extragalactic expedition, the CT1 8.5x17mm pistol cartridge was put to use mostly in self-defense handguns, though it was also favored over CT2 for use in submachine guns for its lower weight and recoil, making submachine guns and pistols chambered for it smaller, lighter, and easier to control, as well as allowing larger magazine capacities. They were not favored where absolute lethality was a concern, where hollow point CT2 was preferred.

#### E7-CT2 (aka 10.98x21mm)

Ballistically and dimensionally similar to .45 ACP, the authiik CT1 cartridge is most commonly used in police and military handguns. Its large and heavy bullet is said to have more "stopping power", causing more damage to the target and incapacitating them more easily, and its size and weight lowers the chance of penetrating all the way through walls or people, making urban and indoor combat less dangerous for innocents in apartments on the other side of walls or people. Their size increases the recoil and weight of firearms that chamber it, and lowers the overall magazine capacity.

#### E7-CT3 (aka 6.1x25mm)

The CT3 took the opposite approach to the CT2. A bottlenecked small caliber pistol cartridge intended to push a small, light, pointed bullet as fast as is physically possible while still being small enough to be chambered in pistols. This improves penetration of softer surfaces and body armor but also increases the penetration of flesh, making overpenetration an issue unless the bullet is designed to fragment inside the body. Fragmenting bullets are worse at penetrating armor, however. Its case head diameter is roughly the same as CT1, which maximizes magazine capacity.

#### E7-CT4 (aka 6.1x34mm)

CT4 is a cousin cartridge to CT3, but was intended for personal defense weapons. It uses the same diameter of bullets as CT3 but roughly 35% longer, and a casing that was roughly 9mm longer. When fired from rifle-length barrels, or even carbine-length barrels, this provides them with more power, better range, and better armor penetration capabilities than even CT3 pistol cartridges, and more controllable automatic fire than intermediate automatic rifles. As with human PDW-class firearms, they were popular with police forces and were given to vehicle operators and medics, signalers and artillery operators, special forces troops, and even cooks and armory officers. Personnel that were expected to be near the front lines but not actively participating in open combat.

### Authiik Linear Accelerator Slugs

#### E7-ES1 (aka 6.1x20mmEMS)

A slug with a more traditional bullet-like shape, the E7-ES1 was used in authiik anti-personnel magnetic accelerator carbines. A number of different projectiles from non-lethal rubber pellets to standard jacketed lead bullets, and from tungsten armor penetrators to low-mass high explosives with a diameter of 6.1 millimeters and a maximum length of 24.4 millimeters, were placed into a 20mm long cylindrical aluminum sabot that was discarded upon reaching the end of the rails. This sabot was secured together by small amounts of adhesive and shallow interlocking surfaces, and was shed via rotational energy imparted by the weapon's helical rails and by air resistance caused by open cavities on the front of the sabot, allowing air into the projectile chamber which aids in forcing the sabot apart.

#### E7-ES2 (aka 12.2x130mmEMS)

The ES2 was a more specialized projectile than ES1, with a large sears-haack profile projectile in a similar sabot intended for high-mach projectile speeds. Its high volume makes it ideal for anti-vehicular action through depleted uranium penetrator rounds, or polymer-body explosive rounds. It is not used for anti-personnel fire

### Other Known Authiik Ammunition

As more of the authiik starships were searched in the following days more cartridges were discovered among the personal belongings of the authiik that were not stored in the armories, instead locked in cases beneath beds or in lockers near practice ranges. Some authiik prefer to own weapons in other calibers than what is standardized upon, mostly for the sake of variety.

#### E7-CT9 (aka 4.88x37mm)

CT9 is a very small high-velocity intermediate rifle cartridge used in personal light carbines and competition rifles. Its light weight and narrow diameter allows higher capacity magazines than military 7.35x41mm intermediate ammunition, but its 3.1 gram, 4.88 millimeter bullet lacks the terminal effect of the larger 7.35 millimeter bullet. This endears it to being a civilian competition cartridge more than anything else, and as such it was found in a number of select-fire carbines with two-round burst modes.

#### E7-CT10 (aka 6.7x15mm)

CT10 was a small and lightweight pistol cartridge that was chambered in just about any size of weapon, from simple and inexpensive practice rifles to competition target shooting pistols. It was cheap and plentiful, but not very deadly in comparison to most any other cartridge.

#### E7-CT11 (aka 4.88x20mm)

CT11 was a miniaturized CT3 cartridge popular for small, high fire rate submachine guns. It had a 0.5355 milliliter case volume with a light 2.18 gram bullet. It followed a very flat trajectory at a very high velocity.

#### E7-CT12 (aka 12.2x23mm)

CT12, or 12.2x23mm, is a low-volume production cartridge popular specifically on the sixth section of the fifth extragalactic fleet. It was a slow and heavy .48 caliber pistol cartridge used in personal self-defense pistols. Chamber pressures are similar to the CT1 light pistol cartridge but its larger caliber and heavier bullet gives it significantly different characteristics that some consider desirable, as anything outside of lead-core full metal jacket ammunition is restricted to service weapons only.

### E7-CT13 (aka 4.88x26mm)

CT13 is a short, narrow, tapered micro-caliber PDW cartridge intended for use in small, high rate of fire automatic carbines.

#### E7-CT14 (aka 7.07x21mm)

CT14 is a popular personal handgun cartridge that was commonly found with both a 4.71 gram polymer jacketed solid copper bullet and black polymer case with a brass insert for the rim. More traditional hollow point copper-jacketed lead and steel examples were used as police ammunition on Mabatshar.

### Obsolete Ammunition

Obsolete ammunition is ammunition that is quite old, in some cases dating back millennia, such as large caliber black powder cartridges or early smokeless powder ammunition, and often not made in bulk. Small quantities of cases are made and the customers are meant to assemble it for themselves, often also with small production quantity bullets of odd calibers. These cases are typically brass, as they are far more durable after repeated use then steel cases, and especially more than aluminum cases, though they are quite a bit heavier. See "Historic Authiik Firearms" cartridge sections for more details.

## Cartridge-Firing Weapons

Most authiik weapons are similar in operation to those of humans, with hammers and strikers used to either hit or provide spring pressure to a firing pin, which strikes the primer of the cartridge in the chamber, which ignites the powder, building pressure inside. The bolt head's lugs in their recesses and the chamber walls prevent the pressure from rupturing the case, forcing the bullet to exit the casing and travel down the barrel.

The barrel features helical ridges on the interior surface of the barrel which are a slightly smaller diameter than the bullet, which are known as rifling. These create indentations in the bullet and force it to spin, which gyroscopically stabilizes it. This prevents it from tumbling in the air and allows it to fly straighter for longer.

The method of opening the bolt again after the initial shot varies from weapon to weapon, with some requiring manual operation, and others tapping energy from the recoil or expanding gasses to force the bolt backwards.

### Rifles

#### E7-GRS1-IAR

The Gas-Operated Rifle System 1 Infantry Assault Rifle, also known as the Izhbanakeh, was the standard Authiik infantry rifle aboard the fifth fleet when it arrived at Temno. It was a short-stroke annular gas piston-operated, roller locked, magazine fed bullpup assault rifle chambered for the 7.35x41mm CT5 cartridge. It has a barrel length of 419 millimeters and an overall length of 701 millimeters. Its simple tubular construction was contained within an aluminum receiver, functioning by way of an annular gas piston, a ring that surrounded the barrel and pushed back on the long tubular extension of the bolt carrier.

It worked similarly to firearms like the Lewis Automatic Rifle, German FG42, and British Thorpe EM rifle prototypes. A fixed firing pin on the bolt carrier that can only protrude when the bolt is fully in battery. The bolt carrier is held back by a notch cut in the operating rod. This gave it a similar fire control mechanism to many open bolt firearms, simply dropping a sear allowing the carrier to travel the final centimeter, forcing the bolt to close and lock before the primer is detonated.

When the rifle fires, the gas is redirected to an annular ring 3/4 of the way to the muzzle. This ring is forced back by the expanding gasses, which forces the long tubular carrier to move backwards, unlocking the bolt and ejecting the empty casing before returning to battery with a fresh cartridge.

Its progressive trigger means that while after the first shot has been fired and the trigger disengaged from the sear, continuing to pull back farther will reengage the sear and allow automatic fire.

A variant known as the Azhibiideh, or GRS1-DMR, is the designated marksman's rifle used alongside the infantry assault rifle GRS1-IAR. It is equipped with a 3x magnified optic in place of the sights and carry handle, an extended length barrel and handguard, a bipod, and reduced length 14-round magazines. Its fire control group has been restricted to semi-auto only.

The rail system is distinct from the civilian pattern. Instead of adding materials, instead holes are cut into the handguard. An aftermarket front handguard exists that adds more typical rails but this is not used by the military.

#### E7-GRS2

The Gas-Operated Rifle System 2 was a popular personal rifle pattern. A long-stroke gas piston operated, lifting bolt, magazine fed assault rifle that was most often chambered in 4.88x37mm CT9. Its "rifle" configuration uses a 374mm barrel with seven-sided polygonal rifling at a 16.5 centimeter twist rate, and its "carbine" configuration uses a 272mm barrel. The shorter barrel also necessitates a shorter gas system, which gives the rifle a greater recoil impulse and a lower muzzle velocity.

Its bolt, carrier, barrel, trunnion, and fire control parts are made from steel, and its receiver, handguard, grip, and stock are made from polymer. As expected from an authiik rifle, it is roughly 85% the size a human equivalent rifle would be, at an overall length from flash hider to butt pad of 869.6 millimeters.

Similar to the German STG44, NATO's FAL, the Soviet SVT-40, and many other weapons of human design, the bolt (in red in the above diagram) does not rotate. It instead is lifted and lowered into recesses and behind lugs that keep the bolt from moving backwards under firing pressure. At the front, a triangular notch is hooked onto the rear of the feed ramp, and at the back, a set of six small square lugs are interfaced against six matching rail-ends in the trunnion (in green).

After the bullet reaches 70% of the way to the muzzle, it passes the gas port, causing the barrel (in yellow) to begin venting gas pressure upwards and into the gas block (in orange), forcing the gas piston backwards. This piston is pinned to the bolt carrier (in blue). When the carrier moves back, the bolt is cammed upwards 2.85 millimeters, which clears the locking surfaces and allows the bolt to move back. The telescoping recoil spring (in purple) forces the bolt forwards after the empty casing has been ejected.

As the rifle is designed to be as ambidextrous as possible, the ejector is a modular and reversible component that locks into either the right or left side ejection port. It is made from a simple rocking lever that is forced to rotate by the passage of the bolt. Further ambidextrous features include the safety and the charging handle.

Its fire control group (in white) resembles that of the US M1 Garand rifle and moreso the later Soviet Kalashnikov rifles, of which some variants and descendants are still used in some parts of human space, most notably the human colony of Temno. The hammer is held down by one hook on the trigger, and when it is forced down by the bolt it is caught by a second hook on the disconnector.

When the trigger is pulled in the "fire" position, marked with the number 1, the hammer is freed from the trigger to hit the firing pin on the back of the bolt. When the bolt moves rearwards it is forced down and engages the hook on the disconnector. When the trigger is released, the disconnector is moved back, allowing the hammer to move forward slightly, which returns it to the hook on the trigger. In the "safe" position, marked with the number 0, both the trigger and the disconnector are held down, which doesn't allow the hammer to be released at all.

In the middle "auto" position, marked with the number 40 (octal equivalent to 32), the disconnector is held down which does not allow the hammer to hook onto it when it is forced back. In addition, the auto sear becomes useful. This is a simple wedge that pushes back into a matching notch in the hammer that stops it from following the bolt home. This prevents light strikes. The bolt moving into battery pulls it away from the hammer and allows it to fall again.

### Submachine Guns

#### E7-DCS1

The DCS1, or delayed blowback carbine system, is closely related to the GRS1, in that it is a bullpup submachine gun that uses a semi-open bolt mechanism not unlike the Lewis Automatic Rifle or German FG42. It also resembles the GRS1 in design, as it had a common origin before their departure from their territory before the exodus.

#### E7-BCS1

The Blowback Carbine System 1 is a simple open-bolt, automatic only blowback submachine gun chambered for 4.88x20mm CT11. With a magazine in the grip and an unusual arced path that the bolt travels on under recoil, it is extremely compact.

#### E7-BCS2

The BCS2 is an even simpler weapon than the BCS1, manufactured in large numbers on Mabatshar. Made from a simple tube with a cutout for the ejection port and charging handle, a cast aluminum fire control group and magazine well, and 24-round polymer magazines, its only milled components are the barrel and bolt. It is chambered for the 6.1x25mm CT3 cartridge, firing from a 260mm barrel at an overall length of 583 millimeters.

Made to be extremely inexpensive, the BCS2 was the standard infantry carbine used on Mabatshar after the extragalactic expedition fleets left the galaxy. Its small-caliber, high velocity pistol cartridge served as a suitable substitute for more powerful rifles while decreasing the materials required to produce it, as well as simplifying the design of the carbines designed to use it, functioning as linear hammer-fired open bolt select fire weapons.

Its fire control group resembles that of the GRS1 Izhbanakeh rifle and the DCS1 Masiika sub machine gun, a progressive trigger with a simple dropping sear to release the hammer. The first bit of travel drops the sear while the recoil of the shot forces the trigger to disconnect, but pulling farther reengages the sear and allows automatic fire. This suggests that the weapon shares a lineage with the two more sophisticated weapons platforms that were retained on the fleets.

### Sidearms

#### E7-RSS1

The Recoil-Operated Sidearm System 1, known as the Damazhera Zhot, "Stinger", or "One who Stings", is a very common and very plain light support sidearm used by individuals, security officers and law enforcement on the extragalactic fleets. It uses a method of operation familiar to humans, a short recoil, linkless tilting barrel system and a shrouded single-action-only hammer. A combination of features that has been used in human handguns since the early twentieth century.

The use of a slide keeps the size of the weapon down while maintaining the required mass to keep the breech closed long enough to fire the cartridge safely. The locking surface is the face of the square chamber that protrudes upwards from the ejection port until, under recoil, the slide and barrel reciprocate together, causing the barrel to interact with a camming surface that pulls the barrel downwards slightly. This allows the slide to open and eject the empty case before returning to battery with a fresh cartridge. The top-mounted extractor serves as a loaded chamber indicator, popping up when closed on a cartridge.

At an overall length of 165 millimeters, a height of 109 millimeters, and a barrel length of 87 millimeters, it would fit into the human category of the compact pistol. Its frame is made of polymer while the fire control parts, slide, and frame are made from steel. It chambered the 7.07x21mm CT14 cartridge from a 12 round magazine in the grip, though they could also be found in other calibers up to as large as 12.2x23mm CT12, though that cartridge has a maximum magazine capacity of 6 rounds. All of its controls and ergonomics are ambidextrous, with a slide lock lever on both sides and a magazine release that requires two buttons on opposite sides of the grip to be pressed together.

## Magnetic Accelerator Weapons

### E7-MWS1-DHHAC

The authiik Masharii Ayomanii Kavaii 22-Vii1, designated by humans as the Extraterrestrial 7 Magnetic Weapon System 1 Dual Helical Homopolar Accelerator Carbine, is an advanced authiik infantry railgun. It was a further development of the Ayomanii Kavaii 22, or Ayomanii Model 22, prototype railgun built by Masharii armories on the fifth galactic fleet post-exodus, making it a relatively recent invention for their species. In terms of the lives of the fleet's members it was invented within the last few decades, even though on a universal time scale these weapons sat unused in armories for millennia.

Its sub-designation of "DHHAC" refers to its quad rail system, using alternating pairs of titanium-core helical copper coated rails to fire slugs. These rails were surrounded by a thin layer of dense insulating material inside of a titanium cylinder intended to reinforce the rails and ensure they are bent as little as possible upon firing. This makes weapons much more expensive, but also allows for higher rates of fire, more effective dissipation of heat, and spin-stabilization on the part of the rifle and not the projectile.

It feeds 48 rounds of ES1 6.1x20mmEMS sabots from a side-mounted box magazines that lie parallel to the barrel, while the sabots themselves are perpendicular to the barrel, pointing upwards. At the end of the magazine is a spiral ramp that causes the rounds within to rotate and face forwards for feeding.

The mechanical portion of the weapon system, upon the pulling of the trigger, pushes forwards and strips a sabot out of the magazine and into the rails. Upon contacting the rails, one of two capacitor banks will discharge, sending electrical current through the positive rail, across the sabot, and back through the negative rail and launching the sabot away from the barrel at a velocity of roughly 900 meters per second with a full discharge. Its battery pack must be recharged or replaced after roughly twelve full magazines, between 550 and 600 rounds fired. As its firing is entirely electronically controlled, it can be tuned by the user to their preferred speed. Its maximum fire rate was 768 rounds per minute.

In automatic mode, this mechanical system will continue to push sabots into the rails, alternating between the first and second capacitor banks and by extension the first and second pairs of rails, until the magazine is empty. In semi-automatic mode, the trigger must be released between shots, but the rail pairs still alternate in an effort to level the wear between them. The rails have an effective life of close to six thousand fired rounds, after which they become too disfigured to fire accurately enough for service. These discarded rails have their copper coating stripped off and their titanium alloy cores used to create new rails.

Its standardized sight was a two-position rear aperture and front post combined with a small computer display. The status display tracked the number of sabots left in the magazine, the current charge status of the capacitor banks and energy cell, and the approximate condition of the rails based on when they were last changed and how many rounds had been fired since. If needed, these can be swapped for magnified optics or other types of sights.

### E7-MWS1X-HHAC

The MWS1X-HHAC, or Magnetic Weapon System 1 Experimental Helical Homopolar Accelerator Carbine is the predecessor to the MWS1, identified as the Mashari Kavai 22 among the authiik. It was mostly similar to the later model but had a lower maximum charge of seven magazines, between 300 and 350 shots fired, a lower muzzle velocity of roughly 700 meters per second, and a lower maximum fire rate of 412 rounds per minute as a result of having only one set of rails.

The two weapons also differ in their external appearance. The MWS1 was finely finished, with a sleek polymer and magnesium housing covering the machines and electronics that made up the functional portions of the weapon. The MWS1X was much more primitive, made up of steel plates and access ports so if anything was to break, it could be quickly accessed for inspection.

## OLD

### Rifle Calibers (OLD)

#### CT6 (8.78x78mmB)

The CT6 cartridge, with the metric designation 8.78x78mmB, is a belted magnum rifle cartridge used in the authiik military for the purposes of extreme long-range marksmanship, armor penetration, and ordnance disposal.

#### CT5 (7.33x50mm)

The CT5 cartridge, with the metric designation 7.33x50mm, is the standard full-power rifle cartridge for the authiik military, serving in a similar role to NATO's 7.62x51mm cartridge. It is the most common caliber used for sniping and in emplaced machine guns, as the heavier bullets maintain their trajectories better than the CT4 does. It also is used by many civilian weapons.

#### CT4 (4.88x42mm)

The CT4 cartridge, with the metric designation 4.88x42mm, is the standard intermediate rifle cartridge in the authiik military, used for designated marksman rifles, assault rifles, light machine guns, and squad automatic weapons. It replaced the 7.33x50mm cartridge used in battle rifles by many nations on Udyana. Many civilians use this caliber as well, which ensures equipment compatibility between military and militia weapons.

### Handgun Cartridges (OLD)

#### CT3 (8.78x29mm)

The CT3 cartridge, with the metric designation 8.78x29mm, is a magnum automatic handgun cartridge used mostly in machine pistols, which occupy special purpose roles with the authiik military and are often used for recreational competition among civilians.

#### CT2 (8.78x22mm)

The CT2 cartridge, with the metric designation 8.78x22mm, is an automatic handgun cartridge used in older model submachine guns and handguns, though it is still popular with civilians for their handguns in much the same way humans use 9x19mm Parabellum.

#### CT1 (4.88x20mm)

The CT1 cartridge, with the metric designation 4.88x20mm, is a bottlenecked handgun cartridge used in modern authiik SMGs and pistols. Its small size allows it to fill magazines more efficiently, with more cartridges for the same weight as CT2 cartridges at the same terminal effect.

### Cartridge Firing Weapons (OLD)

#### "Aderazeh" Series

The aderazeh weapons are the most common rifles and carbines in the authiik military, making up the designated marksman's rifle, the assault rifle, and the submachine gun, unified by their similar construction and layout. All of the weapons are in a bullpup configuration and have a tubular receiver, a full hand trigger guard, and all models accept the same default holographic iron sight base.

The sight base, doubling as a carrying handle, attaches to the slots on the handguard and receiver via a protrusion on the front and a metal hook attached to a serrated square button on the rear surface. The posts on its upper surface feature lights that project the rear arrows and front dot onto a thin mist, and serve as backup iron sights in case of battery failure or disruption. The dial serves to raise and lower the rear sight posts to adjust for range, and the arrow buttons adjust the brightness of the holographic projections.

#### ACAR-1/2 Platform

The Ibaznakeh, designated as the Authiik Cartridge Firing Automatic Rifle 1 (ACAR-1), was the midsize military pattern weapon, an assault rifle with a 401 mm barrel, not including the length of the flash hider, and a select fire trigger pack. The Azibiideh, designated as the Authiik Cartridge Firing Automatic Rifle 2 (ACAR-2), was the largest of the three military weapons and served as the standard designated marksman's rifle, featuring a 596 mm barrel with ports to act as a built-in muzzle brake, and a semi-automatic trigger pack.

Both rifles used an annular long stroke gas piston system, which surrounds the barrel and chamber and connects to the bolt carrier via screws. The firing pin is directly connected to the bolt carrier in much the same way as that of the German FG42 was. In an ACAR-2, the sear that holds the bolt closed without the operating rod coming all the way forward. This sear lowers, allowing the gas piston to continue forwards to impact and ignite the primer of the chambered cartridge.

In ACAR-1 trigger groups, there are two sears. The first functioned the same way as that in an ACAR-2, while the second allowed for fully automatic fire via an open bolt much like the operation of a Lewis Gun, and the automatic fire mode of the FG42.

As the bullet passes the gas block that surrounds the barrel, gas pressure vents through two small holes on either side of the barrel, which travels rearwards to impinge on the front of the operating rod and gas piston, forcing it and the bolt carrier backwards. This causes the locking lugs on the bolt to rotate out of their recesses on the barrel extension allowing the bolt to open. The bolt then continues backwards to eject the spent case and as it returns, it pushes a new cartridge forwards out of the magazine and into the chamber.

The bolt will then lock onto the sear if in semi-auto, or continue fully forwards if in full-auto, allowing the process to be repeated. The gas system on the ACAR-1 is shorter than that of the ACAR-2, giving it more violent recoil impulse and a higher fire rate than the longer rifle.

#### ACAC-1/2 Platform

The Masiika, designated as the Authiik Cartridge Firing Automatic Carbine (ACAC-1), is an open-bolt, full-auto only submachine gun with a 246 mm barrel and a very simple sear mechanism allowing for the release of the bolt, with a fixed firing pin that ignites the cartridge's primer when the bolt closes. The weight of the bolt and springs prevents the bolt from opening until pressure within the barrel has dropped to safe levels. The barrel is secured in place via a trunnion and four pins, with two on each side. The rear of this trunnion and the face of the chamber are the surfaces the bolt impacts when closing.

A long barreled select fire model is popular for use in civilian competitions where long range targets are not a factor, due to cheaper ammunition supply and lower recoil than the ACAR-1/2 platform, and greater muzzle velocity and accuracy than the military pattern ACAC-1 as a result of the longer barrel and closed bolt, operated by a linear hammer instead of simple open bolt.