Notes: This is a bullpup version of the various AK-series weapons, generally sold as a kit to convert existing AKs rather than a full weapon. It was not a Russian weapon, but instead was sold in the US and Europe, as well as some other parts of the world, by a couple of American companies. It was one of the few bullpup rifles available to the general public before the war, most bullpup weapon being produced exclusively for military and police forces. The conversion from standard AK to AKU-94 configuration takes about 2 hours and takes an Easy: Gunsmith or Difficult: Small Arms (Rifle) roll. The resulting weapon is over 25 centimeters shorter, but has a creepier trigger pull. In addition, the construction of the AKU-94 is such that left-handed firers tend to have the charging handle hitting their face during firing, so it is definitely a right-handed weapon. The new weapon is also not as well balanced as a standard AK.

Twilight 2000 Notes: Though there were some reports of Russian and Chinese troops using these weapons, the reports of Russians using them are probably misidentified OTs-14s, and the Chinese weapons were probably locally-manufactured weapons of similar design and characteristics. Though there were some civilians who had this modification done to their weapons, the AKU-94 was never a widely-used weapon, and most of them were made from AK-47s or AKMs. There were most likely almost no conversions of AKMRs to this standard, but such a modification will exist only in the Twilight 2000 world.

Merc 2000 Notes: This is mainly just a novelty type of conversion.

Notes: This is basically an AR-15 carbine modified to fire 5.45mm Kalashnikov ammunition (which Alexander Arms calls the .21 Genghis round; Alexander Arms’ round does differ in several ways from the 5.45mm Kalashnikov, but not in any way that can be simulated with Twilight 2000 game mechanics). The Genghis features a 16-inch barrel; it is not typically equipped with a flash suppressor, being designed primarily for the civilian market, but does have a MIL-STD-1913 rail instead of a carrying handle, and is built to otherwise meet or exceed military and police specifications. (Versions with carrying handles instead of MIL-STD-1913 rails are also available.) Ten-round magazines are normally supplied with the Genghis, but modified AR-15/M-16 magazines with larger capacities are also available.

Twilight 2000 Notes: This rifle is not available in the Twilight 2000 timeline.

Armalite AR-18

Notes: This weapon was designed in the 1970s with experience gained from the M-16 series. Armalite found that there were a lot of countries that wanted to license-produce the M-16, but did not have the modern facilities required to produce the more complicated M-16. The AR-18 was designed to be simple and cheap to produce, as well as being relatively "soldier-proof." The US Army tested it, but did not produce it; it was then licensed to Howa Machinery in Japan, NWM in the Netherlands, and Sterling in Great Britain. They also got virtually no military contracts, and Sterling sold its license to a company in the Philippines (who also got no military sales). Much more lucrative was a semiautomatic civilian version, the AR-180; tens of thousands of AR-180s were sold to civilians in various countries. The AR-18S is a shortened AR-18, similar in concept to the CAR-15. Bayonets and rifle grenades can be used, if the flash suppressor is removed.

A later civilian version, the AR-180B, is somewhat different than the standard AR-180 and bears some elaboration. The AR-180B uses a lower receiver made from polymer strengthened with a steel liner. The shape of this lower receiver mimics the original lower receiver exactly, so that an upper of an AR-180 may be placed on a lower from an AR-180B and vice versa. The trigger group of the AR-180B is borrowed from the AR-15 instead of being the original AR-180 design. The front and rear sights are also borrowed from the AR-15A2, though the protective ears are different from those of the AR-15A2, and there is no elevation adjustment wheel on the AR-180B (elevation adjustments are done on the front sight). The scope mount is of original AR-180 design. There is a new design magazine well which allows the use of AR-15, M-16, and AR-18 magazines. The magazine release button is thus the same as on an AR-15, and there is a small protrusion to prevent its being pressed accidentally. The AR-15 has a sort of "half-pepperpot" muzzle brake instead of the original flash suppressor. The barrel is slightly longer at 19 inches.

Twilight 2000 Notes: Starting in 1995, production of military AR-18s started again in the Philippines and Great Britain, who managed to sell a large amount of them to African and Southeast Asian countries. Sterling later produced more for issue to local militia units loyal to the Crown. NWM in the Netherlands also produced some AR-18s, and they were used by Dutch and Luxembourg resistance fighters against the French. In the US, many as Russian or Mexican soldier (or sometimes, Milgov, CivGov, or New American soldier) discovered that their enemy was a local militia soldier armed with an AR-180 or AR-180B converted to automatic fire.

Merc 2000 Notes: This was surprisingly common in issue to people working for US or British intelligence, due to the problem with tracking down exactly who made the weapon, and the ease with which its parts could be made.

Notes: The M-15 is essentially a modernized version of the AR-15, and may also be regarded to some extent as a smaller version of Armalite’s New AR-10 Series. The M-15 comes in four basic versions: the M-15A2, basically very similar to the AR-15A2, but with a heavy barrel, muzzle brake, carrying handle a la AR-15, and round handguards and a stock similar to those of the AR-15A2. The standard barrel is 20 inches, but there is also a carbine version with a 16-inch barrel. The M-15A4 is basically the same weapon as the M-15A2, but uses a flattop upper receiver with a MIL-STD-1913 rail. The M-15A4 is meant to be used with various optics, but there is a very short MIL-STD-1913 rail in front of the handguards, and iron sights may be attached to the two rails. The A-15A4 is a little lighter than the M-15A2. The M-15A4(T) is a target version of the M-15A4; the rifle version uses a 24-inch heavy barrel which is target crowned and designed for accuracy, and it has no muzzle brake or flash suppressor. The upper receiver is flattop and has a MIL-STD-1913 rail, and the handguards are round and made from aluminum. There is also a carbine version of this weapon; this has the heavy target barrel, but it does have a muzzle brake and the barrel is only 16 inches. The trigger of these two versions is a National Match two-stage trigger. The M-15A2 and A-4 Carbines are special models designed for military and police use; they may have automatic fire capability as options, use an M-4-style folding stock, and may have a 14.5-inch or 16-inch barrel with a flash suppressor instead of a muzzle brake. The M-15A4 LE Carbine is flattop; the M-15A2 LE Carbine has a carrying handle.

Notes: The idea behind this weapon was to produce a compact version of the M-16 while avoiding the massive muzzle blast and firing signature that such a weapon normally produces. To this end, Arms Tech used a standard M-16 lower receiver and paired it with a modified upper receiver using a specially designed barrel shroud/muzzle brake. The standard buttstock was replaced with a sliding wire stock, and the carrying handle was replaced with a MIL-STD-1913 rail (the stock Compak-16 comes with an Occluded Eye Sight licensed-produced from a South African design). The cyclic rate has also been reduced to 600 rpm (though this has no effect game-wise). The rifling allows for the effective use of either SS-109-type or M-193-type ammunition, as well as subsonic rounds. Arms Tech has also designed a silencer for use with the Compak-16, which is easily attached and removed, as well as one which replaces the barrel assembly and becomes an integral part of the Compak-16.

Twilight 2000 Notes: Though it had little success with the military or police, survivalists and militia members in the US liked the Compak-16, especially female members.

Merc 2000 Notes: This is mostly a civilian niche weapon, though there has been some experimentation by the US military, the CIA, and various Federal agencies.

Notes: This modification of the M-16/M-4 series was designed specifically for use by US special operations forces. The weapon was initially tested in very limited quantities in Afghanistan starting in 2002, and some are also being used in Iraq. The M-468 is essentially a stock M-4 or M-16 lower receiver with a new upper receiver and barrel designed by Barrett, ad firing new ammunition designed by Remington. The new upper receiver has a bolt carrier group designed for the new cartridge, and the weapon is fed from modified M-16-style magazines. The upper receiver is fitted with a MIL-STD-1913 rail in lieu of a carrying handle, there are four further such rails on the handguard, which is similar to that of the M-4 SOPMOD. Folding iron sights are fitted to allow clear use of optics and accessories.

Recently, a version with a short 12.5" barrel and the capability to mount a suppressor has been designed. This version is primarily aimed at military users (particularly special operations), and a civilian version is not planned, as the barrel is too short for legal civilian sales in the US. In this version, the muzzle brake is much more beefy, and a sliding stock is standard.

The model number "468" refers to the year 2004 (the official date of entry into military stocks) and the caliber (6.8mm). Barrett also has plans to produce a semiautomatic version for civilian use, without all the bells and whistles.

Twilight 2000 Notes: This weapon does not exist in the Twilight 2000 timeline.

Notes: Introduced in 2004, this is a truly weird small-caliber weapon: a belt-fed, rimfire carbine. It is normally only available in semiautomatic form, but an automatic version is available to Class III dealers or police, military or certain government agencies. Currently, the stocks are made of laminated walnut, but other stock options are promised for the future. The BF1 can take clip-on and bolt-on bipods without modification, but a bipod is not provided as standard equipment. The sights are a proprietary design and consist of a combination of a post rear sight and a front sight called a "spade" (due it’s shape being reminiscent of a spade in a deck of playing cards). This system helps cut down on target obstruction from the sights themselves. Current BF1’s are chambered for .22 Long Rifle and .17 Mach 2 Rimfire, but in the future, Eric Graetz (the designer) plans to chamber the weapon for .22 Winchester Magnum Rimfire and .17 Hornady Magnum Rimfire.

Twilight 2000 Notes: This weapon does not exist in the Twilight 2000 timeline.

Notes: This has been described as an improvement over the original Carbon-15 by Professional Ordnance. (Bushmaster acquired the Carbon-15 after Professional Ordnance declared bankruptcy in 2002.) It is, in appearance and operation, quite different from the AR-15, from the lightened stock to the "miniaturized" bolt carrier group. The biggest difference is the use of light carbon-fiber construction in the new stock, handguards, and even the upper and lower receiver housings. The bolt carrier group is much shorter than the standard AR-15 bolt carrier group due to the deletion of the forward assist; it is felt by Bushmaster that its Carbon-15 design, together with improvements in ammunition, make the forward assist unnecessary. The selector controls are ambidextrous. The Carbon-15 uses a flattop receiver; a MIL-STD-1913 rail extends from the rear of the upper receiver to the end of the handguards. The barrel is heavy, but made of lighter alloys and is fluted, further driving down the weight without compromising accuracy. The Carbon-15 has a new muzzle brake that is extremely effective, actually driving the barrel down when firing. At present, the Carbon-15 is available only in a semiautomatic version, but an automatic version is contemplated for the future for law enforcement and military use.

A post-ban variant of the Carbon-15, the C-15M4 (Carbon-15 Model 4) is an M-4-style Carbon-15 which still has the carbon-fiber upper and lower receiver and handguards, but there is also a partially-synthetic collapsible stock. The barrel is similar to that of the standard Carbon-15, but is not fluted. Unlike the Carbon-15, the C-15M4 will accept standard M-16/AR-15/M-4 parts. The C-15M4 uses standard AR-15/M-16/M-4 magazines; automatic versions are sold only to military or law enforcement concerns. Another post-ban variant of the Carbon-15 is the Carbon-15 in 9mm Parabellum; this version is basically a C-15M4 rechambered for 9mm, with appropriate changes in the sights. Though technically a submachinegun instead of an assault rifle, it is included here for completeness.

Twilight 2000 Notes: This weapon does not exist in the Twilight 2000 timeline.

Notes: This weapon was originally designed in Australia by a company named Edenpine, and meant for sale on the civilian market. Edenpine realized that Australia’s rather restrictive civilian firearms laws would severely limit its sales in that country; therefore, Edenpine reached an agreement that Bushmaster would build and sell the M-17S under the Bushmaster name, with Edenpine receiving royalties from each sale as well as money from the licensing of the design.

The M-17S is basically a bullpup version of the AR-18 in a semiautomatic version. The Bushmaster company made no apologies for the fact that it would use any magazine that would fit in the AR-18, AR-15, or M-16 series, nor the fact that it could be very easily converted to automatic fire. The operating parts of the M-17S are largely made from stainless or chrome-plated steel, with the upper receiver being made almost entirely of a single aircraft-grade aluminum extrusion and the lower receiver from fiberglass-filled nylon composites. Because of the bullpup layout, Bushmaster was able to lengthen the barrel to 21.5 inches, giving the M-17S greater accuracy than most assault rifles. The M-17S has a carrying handle topped with a MIL-STD-1913 rail. The M-17S is specifically meant for use with optical sights or other aiming accessories, but it does have rudimentary backup iron sights. The M-17S is no longer in production, but when it was, it was primarily built as a semiautomatic rifle, with a flash suppressor for police/military use or without one for civilian sales. (Rumors state that a small number were also built with automatic fire capability, but this is not confirmed. I have included stats below for automatic fire just in case.)

Twilight 2000 Notes: There was some limited military and police use, but this was mostly a weapon used by civilians and militia forces. Most were found in the US, but some were also found in the UK.

Notes: The Dissipator is a carbine variant of the M-16A2 that uses standard-length M-16A2 handguards and a front sight placed further forward than most carbine variants of the M-16A2. This means that despite the shorter length, the sight radius is almost identical to the standard M-16A2, which allows a little better accuracy. It also allows better dissipation of heat than a normal M-16A2 carbine (hence the name), and means that the Dissipator can mount the M-203 using a standard M-16 interface rather than having to have a custom-made interface.

Other versions of the Dissipator include the Shorty, which has a fixed stock, the Target Model, which is almost identical to the M-16A3 and A4 except for the burst/automatic selector, and semiautomatic-only versions of the weapon for civilian use (these do not have flash suppressors or bayonet lugs, and cost $6 less than their military counterparts). Other than civilian sales, the only large-scale users of the Dissipator series as of 2002 were the US Department of Energy.

Twilight 2000 Notes: As the Twilight War intensified, the US company of Bushmaster became, along with Colt, Armalite, and a few other companies, a major supplier of M-16 series weapons to the US military and its allies. (Some US soldiers were actually equipped with the Dissipator Target Model instead of the M-16A3 or A4.) They did not have much luck with the Dissipator before the war, but as Bushmaster was one of the weapons manufacturers that survived the November Nuclear Strikes, the MilGov asked them to distribute some of their Dissipator Carbines to some of the militia units formed in the aftermath of the nuclear strikes. MilGov thought the carbine would be especially suited to female militia members, and some of the younger members (some militia members were as young as 12 in some places). Bushmaster complied and even manufactured a limited extra quantity, hampered only by irregular supplies of raw materials.

Merc 2000 Notes: As the Notes, except that the Dissipator is also routinely supplied to CIA-equipped mercenaries.

Notes: This is basically an M-16 with a collapsible stock, shorter barrel, and otherwise made as light as possible and still maintain the tactical utility of an M-4. The handguards have 4-way MIL-STD-1913 rails to allow the mounting of as wide a variety of accessories as possible; there is another MIL-STD-1913 rail on top of the receiver, which does not have the usual carrying handle. There are two versions; the military model, as described, and the civilian model, which is semiautomatic only, has no flash suppressor or bayonet lug, and does not have the special handguards.

Twilight 2000 Notes: This weapon does not exist in the Twilight 2000 timeline.

The CAV-15 is an unusual sort of M-4/M-16 clone; the lower receiver, stock, and pistol grip, are made of one piece of composite material, specifically Nylon 6 filled with glass fiber. The handguards are made of the same material. This material is very strong and totally resistant to corrosion. It can also be molded in virtually any color and even to a specific shape if the user is willing to pay, allowing for cheekpieces, individual hand shapes and sizes, etc. The manufacturer, Cavalry Arms, offers a lifetime guarantee on the lower receiver and handguards that they will not break. The company makes the composite components in several different colors: black, green, tan, and even yellow, blue, and pink. The usual M-16/M-4 carrying handle is eschewed in favor of a flat top with a MIL-STD-1913 rail. Four models are available: the Commando, a military carbine not available to civilians; the Trooper, a civilianized Commando; the Scout, a semiautomatic carbine with a longer barrel; and the Rifleman, a full-sized rifle.

Twilight 2000 Notes: This weapon does not exist in the Twilight 2000 timeline.

Colt M-4

Notes: This is a cut down version of the M-16A2, as a CAR-15 is a shortened M-16A1. This weapon, unlike the CAR-15, can mount the M-203. The weapon was designed for paratroopers, to allow them to jump with their weapon uncased (for faster access during combat jumps), but is becoming the standard assault rifle in many other types of US units as well. The British SAS and SBS also use a large amount of M-4s, particularly the M-4 SOPMOD. The M-4A1 is the same weapon, but fires fully automatic instead of 3-round bursts. The SOPMOD (Special Operations Modification) M-4 is a further development of the M-4A1, with the carrying handle removed and replaced by a Picatinny Rail to allow the mounting of a wide variety of sights and visual aids. Another Picatinny Rail may be mounted under the handguard, to allow even more sights to be used simultaneously (such as an infrared sight on top and an infrared pointer on the bottom); alternatively a foregrip, grenade launcher, or modified shotgun may be used. (The type of accessories a SOPMOD M-4 may use is so wide as to be limited only by the imagination of armorers; in game terms, the player who is equipped with an M-4 SOPMOD may choose up to $300 of accessories for his rifle, and these are included in the cost.)

Twilight 2000 Notes: Airborne, special ops, and some Marine units will have these weapons; most other units will not.

Merc 2000 Notes: The M-4 has worked its way into a lot of NATO and US units, and a civilianized version is also available. Civilian versions often have a fixed stock, and sometimes are not equipped with a flash suppressor; they usually don’t have bayonet lugs, either.

Notes: This is the standard combat rifle of the US, as well as having been used or being used by over 50 other armies. The M-16 rivals the AK-series for widespread use. The M-16 is an effective and popular weapon, but is a bit sensitive to dirt. The M-16 was originally designed by the small arms genius Eugene Stoner, based on the AR-10’s action and a development of the .222 Remington round, which was designed to fall in range, penetration, and wounding potential somewhere between the 7.62mm NATO round and the .30 Carbine round. The US Army had expressed a desire (against the wishes of the DoD) as early as 1957 for a light rifle to replace the M-14 as its standard assault rifle, which had already proven to be too heavy for regular troop use and uncontrollable in automatic fire. The prototypes went through several iterations based upon troop and small-arms-expert evaluations. Different ammunition types also were tried, and the AR-15 (as the M-16 was called at the time by Stoner) also faced fierce opposition from the DoD’s Chief of Ordinance, who wanted to stick with the M-14. This meant that official adoption, first by the USAF, did not occur until 1962, who issued it to their security troops), and later that year, for use by SEAL and Special Forces advisors in Vietnam.

Since the SPIW program essentially produced nothing acceptable to the military, Secretary McNamara finally intervened and told the Army to accept the M-16, first for special ops, airborne, Air Cav, and air assault troops, and then later for the Army and Air Force in general. This crash program unfortunately led to quality control problems, which were only partially rectified.

The original M-16 contained most of the features which became standard on future M-16s. It uses the now-standard 20-inch length barrel, though the flash suppressor is slightly different than on later models (though still of the slotted type), and is also made of light alloy instead of the steel of later models. It has no forward assist, and the chamber and barrel are not chromed, which led to quick corrosion and fowling in Vietnam’s climate. (Air Force Security troops, for the most part not operating in such environments or in the bush, didn’t really have this problem.) At the time of issue, the M-16 was still using the IMR Ball propellant recommended by Eugene Stoner, which also greatly decreased fouling and corrosion.

The M-16A1 is perhaps the most common version of the M-16. The original M-16A1s quickly suffered from not being used with IMR Ball propellant (instead, the military decided to go with a much cheaper propellant that caused much more fouling and corrosion, and though they later changed to better-quality propellant, it still did not match the quality of the original IMR Ball propellant), a myth that sprang up among soldiers that the M-16A1 didn’t require any regular cleaning, and a barrel and chamber that corroded rapidly. Thus, the M-16A1 quickly gained a reputation of jamming, usually at the wrong moment. The problems with corrosion were largely fixed by chroming the chamber and barrel. The M-16A1 also introduced the forward assist, which is sort of plunger that can be used to fully close the bolt when the M-16A1 is fouled inside the receiver or otherwise does not seat properly. (This feature as added at the insistence of the Army and Marines; the USAF also has some M-16A1s, but most of them don’t have forward assists, and are often mistaken for original M-16s.) The T-bar charging handle was made wider, the slotted flash suppressor was changed to steel construction (and later changed to the now-familiar birdcage pattern), and the magazines were changed from steel to an aluminum alloy (including a new 30-round magazine introduced in 1969). Most of the problems experienced with the M-16A1 can be traced back to improper maintenance (personally, even though I have always cleaned my weapons thoroughly, have always had problems with extraction failures on both the M-16A1 and A2, however, as did many of my fellow soldiers). The recoil buffer had mass added, which both curbed the too-high cyclic rate and also corrected a problem where the bolt tended to literally "bounce" inside the receiver, resulting in a bolt which did not close properly. It should be noted that in addition to Colt, many M-16A1s were manufactured by GM’s Hydra-Matic division and Harrington & Richardson. (The M-16A1s built by these two alternate manufacturers actually turned out to be superior in quality to those manufactured by Colt!) The M-16A1 has turned up in some strange places; for example, leftist rebels in Nicaragua, El Salvador, and Guatemala were often encountered with it. The serial numbers on the captured M-16A1s were traced to weapons lost or abandoned in Vietnam before US involvement in that country ended. In addition, some 30+ countries are licensed to manufacture the M-16A1, so they may be encountered pretty much all over the globe.

Though the US Army was satisfied with the M-16A1, the Marines were not. In 1980, they began to tinker with the M-16A1, producing the M-16E1A1, which eventually resulted in the M-16A2, which was adopted by the Marines in 1983. Changes made for the M-16A2 included better chroming for the chamber and barrel, a change to a 1:7 rifling twist (from 1:12) to suit the superior SS-109 ammunition which had been developed by FN and Heckler & Koch, the omission of the bottom slot from the flash suppressor (allowing it to function as sort of a partial muzzle brake), and a small block added behind the ejection port to deflect hot brass away from left-handed shooters (hot brass often ends up in the shirts or face of left-handed shooters of the M-16 and M-16A1). The handguard was changed from its triangular cross-section to a round, ribbed criss section; this is not only ergonomically better, but simplifies the supply chain by eliminating the need to have left and right handguard sections. They also dissipate heat better. The pistol grip was also redesigned, with finger swells. The formerly solid polymer stock was replaced with a fiberglass/nylon composite which is filled nylon foam, which helps counteract the fact that the M-16A2 is heavier elsewhere, and is also far stronger than the original stock. The rear sight is replaced by one which allows adjustments for windage and elevation by simple dials (on the M-16A1, windage adjustments had to be made by sticking the point of a bullet or other object into holes in the adjustment dials, and elevation was done on the front post in the same manner). Perhaps the most controversial change was the fire selector; the capability for fully automatic fire was replaced with a 3-round burst feature, with a cyclic rate so high that the recoil from the first round is not felt until the third round is already out of the barrel. The barrel is the subject of more misunderstanding than anything else on the M-16A2; it is roughly double the thickness, but only at about the last third of the barrel. Many think this is to increase accuracy (untrue), to increase heat dissipation (mostly true), and to stiffen the barrel (a little bit true). However, the primary reason for this thickening is a reflection of grunt mentality; the primary reason this was done is to stop soldiers from bending the barrel when using their rifle as an ad hoc crowbar.

The US Army was originally quite reluctant to accept the M-16A2; they did not want to have to switch to SS-109 ammunition since they had mountains of old M-193, and they did not like the burst fire mechanism, as they felt that the ability to produce massive quantities of firepower increased the confidence and morale of its troops. (In essence, they were underestimating their people.) Ironically, a version of the M-16A2 was made with full-auto capabilities, but they were built only for export as the request of certain customers, and not used by the US military. However, in 1985, they were basically forced by the Pentagon to adopt the M-16A2. In addition to the full-auto M-16A2 mentioned above, other versions built for specific export customers include an M-16A2 with full auto features as well as M-16A1-type sights, and an M-16A2 with a medium-weight M-16A1-type barrel.

The M-16A3 is identical to the M-16A2 but has a removable carrying handle that is mounted on a MIL-STD-1913 (for better mounting of optics) and is without burst control. This version is the current standard version of the M-16A1 for the US Army and Marines, and is often seen with an ACOG-type sight mounted on the rail rather than standard iron sights. The M-16A3 also restores the full-automatic feature to the M-16, in lieu of the 3-round burst feature. The M-16A4 is identical to the M-16A2 except for the removable carrying handle and MIL-STD-1913 rail, and uses the selector with the 3-round burst feature.

Other variants of note include the AR-15 HB, also known as the Model 606 or Heavy Assault Rifle M-1. The "HB" stood for Heavy Barrel;" the AR-15 HB was a variant of the M-16A1 designed for use as a squad automatic weapon or as a weapon for what would now be called a designated marksman. The AR-15 HB could take a detachable version of the BAR’s bipod or a standard scissors bipod. The Model 606A was essentially simply a heavier-barreled M-16A1, and the Model 606B was the same weapon, but with an additional selector position to allow burst fire. Only a few hundred were built, primarily for field and combat evaluation use.

The AR-15, AR-15A1, AR-15A2, and AR-15A3 are civilian versions of the M-16/M-16A1/M-16A2/M-16A3; they cannot mount a bayonet, and usually have been "fixed" so that a conversion to automatic fire is beyond the abilities of normal gun owners or even armorers of normal skills. Those few versions built during the Assault Weapons Ban period (even variants built by other companies) usually have no flash suppressor, and were sold with 5 or 10-round magazines (though they can still accept any sort of M-16-type magazine).

Though many special variants of the AR-15 have been made (most by private gunsmiths), some of them include the AR-15 HBAR (Model 611), which is a civilian variant of the AR-15 HB above; it has no bayonet lug nor a forward assist. The Model 611P is a Model 611 built in the Philippines, and the Model 621, which was built for export but is otherwise identical to the standard AR-15 HBAR. The AR-15A2 HBAR (Model 737) is based on the AR-15A2, with the heavier barrel (essentially, the barrel is heavy throughout its length, instead of just the last third); however, it uses M-16A1-type sights. The AR-15A2 Delta HBAR (Model 741) replaces the carrying handle and rear sight with a special mount for a Colt-designed rubber-armored 3-9x sight, and an ambidextrous raised cheekpiece (with an undercut for pulling back the charging handle). The Delta HBAR was introduced in 1987, but was produced for little over a year. The AR-15A3 HBAR (Model 941) is basically the same as the AR-15A2 HBAR, but has a MIL-STD-1913 rail instead of a carrying handle.

Like the M-4, there have been many accessories designed for the M-16 series, ranging from new handgrips to different flash suppressors or even firing different ammunition. The first underbarrel grenade launcher, the M-203, was designed specifically for the M-16A1.

Meanwhile, in Iraq and Afghanistan, the Army and Marines have been using specialist versions of the M-16A3; the Army calls theirs the SDM-R (Squad Designated Marksman Rifle), while the Marines call it the SAM-R (Squad Advanced Marksman Rifle). These are "semi-sniper rifles," designed for sharpshooters assigned to squads of troops who are not trained as full snipers. The SDM-R itself comes in two models – most are in fact based on the M-16A3, but the 82^nd Airborne and 101^st Air Assault Divisions employ many that are based on a flattop version of the M-4 Carbine. (It should be noted that DPMS Panther also makes a civilian model of the SDM-R, which is virtually identical.) The SDM-R and SAM-R use a heavy, match-quality barrel, and the carrying handle is replaced by a MIL-STD-1913 rail which extends from the receiver to the front sight post. No rear iron sights are normally used, but can be added to the rail. The front sight can also be removed as required. The barrel is 20 inches long and is free-floating, but uses a 1:8 twist to accommodate both standard SS-109 ammunition and match-quality rounds, and is made from stainless steel. The trigger and fire mechanism has been replaced by a two-stage match trigger, and the SDM-R and SAM-R are semiautomatic-only weapons. On the handguards is mounted a Harris S-L light bipod, adjustable for height and cant. The M-4-based version is identical except for the 14.5-inch barrel. The cost of these weapons below include a compact telescopic sight.

Twilight 2000 Notes: The M-16A3 and A4 do not exist in as great a quantity in the Twilight 2000 timeline as in the real world; nor does the AR-15A3 and its HBAR variant. The SDM-R and SAM-R were in fact made in the Twilight 2000 timeline, both in the US and by local armorers; however, in the Twilight 2000 timeline, they are called the M-16A3E1 and M4E1.