Notes: Known affectionately by US troops as the "Ma Deuce" or just "The Fifty," the M-2HB was originally introduced in 1923 as the M-1921. Though when the M-2HB was first designed, shortly after World War 1, it was meant to be an antitank weapon, development of tank armor quickly made this idea obsolete. However, since the M-2HB was still a fantastic antipersonnel, antiaircraft, and anti-light armor/soft-skinned vehicle weapon, development of what would become the M-2HB continued, and it has since become the primary commander’s machinegun on Western armored vehicles. Especially during the World War 2 and the Korean War, it was also the primary armament for aircraft on virtually all US aircraft and many Allied aircraft as well. The M-2HB is still manufactured in the US by General Dynamics (and formerly by Saco), in Belgium by FNH, in Britain by Manroy, and to a limited extent by other countries around the world. Many other companies and countries also make spare parts for the M-2HB. Despite recurring rumors of its impending replacement by several newer designs over the years, and despite the fact that the M-2HB is one of the oldest small arms designs still in use in the world, it does seem that the M-2HB will be around for a long time to come.

The M-2HB is tough, heavy, and robust; I’ve personally seen vehicles basically totaled in rollovers, but their externally-mounted M-2HBs were able to be put back into service after just a simple cleaning. Operation is by short-recoil; feed is normally from the left, but a qualified armorer can reverse this. Ammunition boxes can be mounted on a tray which attaches to the M-2HB or its tripod. Originally, both air-cooled and water-jacketed models were made; the water jacket proved to be unnecessary, though that version was used until just after World War 2 as an antiaircraft weapon. The heavy barrel is 45 inches long and though it does have a sort of crowned muzzle, there is no sort of flash suppressor or muzzle brake. Sights are a simple blade at the front of the receiver and an adjustable folding leaf sight at the rear of the receiver; when the rear sight is folded, an adjustable aperture sight is used. There have also been over the years a large amount of basically jury-rigged mounts for various sorts of optics and night vision devices. (The famous Marine Scout/Sniper Carlos Hathcock, holder of the world record for long-distance sniping until recent years, made his longest shot with a scoped M-2HB set on semiautomatic.) There is no stock or conventional trigger mechanism; instead, the M-2HB is fired using spade grips and a butterfly-type thumb trigger. The M-2HB is designed only to be fired from vehicular, aircraft, tripod, or pintle mounts. (I know many of you have seen war movies where the hero picks up an M-2HB and hip-fires it, but I assure you that this is quite impossible!) Just under the trigger is a cylinder/dial; this is in effect a selector device. One rotates it to the right and locks it to allow semiautomatic fire.

However, the M-2HB does have a defect, and it can be a significant one: the variable headspace and timing, which must be adjusted perfectly to allow proper functioning and prevents any sort of quick changing of the barrel. The headspace and timing can also go out of adjustment simply from the vibrations of the M-2HB as it fires. Adjusting headspace and timing on an M-2HB is a difficult and, quite frankly, annoying procedure that takes a lot of practice (and continuing practice) in order to do quickly; a lot of troops literally never manage to do it quite right. And if you don’t adjust the headspace and timing properly, you can end up with an M-2HB that may do anything from refuse to fire at all to one that jams to one that rips brass in half as it extracts. (I have seen a lot of bizarre malfunctions in the M-2HB, virtually all related in some way to incorrect headspace and timing adjustments.)

That said, several countries have been making (for a long time) kits which convert the M-2HB into a configuration that gives it a quick-change barrel and eliminates the need for the headspace and timing adjustments (the QCB, or Quick-Change Barrel kit, in effect provides the M-2HB with fixed headspace and timing which is optimized for the weapon and round). Many nations using the M-2HB, including most NATO countries, have already installed these kits into their M-2HBs. The US, however, as with many things, it a latecomer to the QCB bandwagon; the US military has only recently selected a kit made by General Dynamics (a kit originally designed by Saco Defense all the way back in 1978!) to update the M-2HBs already in service. For the most part, this kit retains the configuration of the basic M-2HB (except for the modifications required to change it to a QCB configuration). The new barrel’s bore, however, is Stellite-lined and chromium-plated. The General Dynamics M-2HB QCB may use standard M-2HB barrels, but this requires removal of the QCB parts and effectively turns it into a standard M-2HB requiring headspace and timing adjustments. The General Dynamics M-2HB QCB is slightly heavier, but its firing characteristics are identical to a standard M-2HB.

Twilight 2000 Notes: Virtually all M-2HBs used by NATO, the US, and other US allies use QCB kits; the one mentioned above was in fact put into high-rate production by Saco Defense as the request of the Pentagon when the winds of war began to blow.

Notes: After experimenting for a while with gas operation, John Browning decided that recoil operation was far better for heavy automatic weapons and developed the M-1917 series of machineguns. He had the design perfected by about 1910, but was unable to interest the US military until World War 1, when the Army suddenly placed a huge order with Browning.

The M-1917 is very similar in appearance to the Vickers and Maxim guns of the same time period, though the Browning gun can be immediately identified by the pistol grip at the rear. More than 68,000 were made before the end of World War 1. In 1936, the weapon was partially redesigned, with the feed mechanism being made more reliable, the sights re-graduated to be more accurate, the tripod made lighter, and other small changes were made. This weapon became the M-1917A1.

The M-1917 is water-cooled, and therefore unsuitable for aircraft operation. The water jacket was removed, and lighter components were used whenever possible, to create the M-1918. The M1919 is similar to the M-1918, but was designed for use on tanks. It also uses a heavier barrel than the M-1917 or M-1918. The M-1919A1 is the same weapon as the M-1919, but designed specifically for the Mark VIII tank. The M-1919A2 is again similar, but with a normal weight barrel. It was designed for horse cavalry, having a special small tripod and a special saddle for transportation. (It cannot be fired from the top of a horse!) The M-1919A3 was a prototype for the M1919A4 (below).

Notes: This weapon was based on an original John Browning design. He was trying to see whether the muzzle blast of an automatic weapon could be put to any use. The result was a weapon that was nicknamed by troops the "potato digger;" the weapon had a swinging arm beneath the barrel that connected to a linkage that opened the breech, and extracted the spent cartridge and loaded another. This arm meant that the weapon could not be mounted too close to the ground unless a pit was dug for the arm. It was a very clumsy arrangement, but the recoil was very mild and the action smooth. In the 1890s, large numbers of the M-1895 were bought by the US Navy in .30 Krag and 6mm Lee calibers; the US Army used .30 Krag and later converted them to .30-06 Springfield. The M-1895 was not used in large numbers in World War 1, though they were used in large numbers for training purposes until almost World War 2. Note: The M-1895 cannot be fired without a tripod or vehicle pintle mount. Tripod weight is 6.1 kg.

Notes: This is an electrically driven 7.62N machinegun used on some US and British armored vehicles. The weapon ejects spent brass overboard and incorporates a fume extractor. This weapon can also be used on a pintle mount, and is installed on some light helicopters.

Notes: This is the US variant of the Belgian MAG machinegun. The first versions of the M-240 appeared in US service as early as 1976 as coaxial machineguns in US tanks, IFVs, and some other armored vehicles; however, the first personnel and pintle-mounted models did not appear until 1994, when the US Marines adopted the M-240G. At first, these M-240Gs were excess US Army and Marine coaxial machineguns modified for ground and pintle use, but these were quickly superseded with purpose-built M-240Gs. By 1996, virtually all M-60s in US Marine use had been replaced by the M-240G, as well as many M-60s in use by the US Navy. The Marines quickly developed a fondness for the M-240G due to its reliability, ruggedness, and easier field-stripping procedures (and, I suspect, because the Marines rarely get first crack at anything new). The US Army, noting these attributes, asked that a forward handguard be added and called it the M-240B; it is otherwise the same weapon.

That said, one of the few complaints about the M-240 is the size of the weapon; at 48.5 inches long, it can be quite the handful for smaller shooters and even a detriment in QCB. Otherwise, the M-240 series has had remarkably few complaints for weapons in US military use. The M-240 series does use a barrel a full 24.7 inches long, and is tipped with a somewhat different flash suppressor than is used by its MAG ancestor. The polymer stock is also different; it actually looks more like the stocks used on current versions of the M-249 than the standard MAG polymer stock, and has folding shoulder plate to help support the weapon when used from the bipod. Sights are also slightly different; the front sight is a protected blade, while the rear is an adjustable aperture sight, which may be flipped up to reveal a U-notch leaf sight. Cyclic rate of fire has been slowed by about 50 rpm, primarily by use recoil springs and buffers which are modified to suit US manufacturing methods. The pistol grip also has a slightly different shape. The M-240G and B are otherwise essentially the same as the standard MAG, except that the M-240 is further modified to allow it to use M-60 tripods and pintle mounts. The US military has also adopted their own version of the MAG’s helicopter door-gun, called the M-240H; this version has spade grips and a thumb trigger instead of the pistol grip and standard trigger group, no bipod, and no handguard. This version can also be mounted on tripods and ground vehicle pintle mounts.

In early 2000, improvements were made to lighten the M-240, resulting in a reduction in weight of 1.36 kg. Starting in 2005, studies were undertaken to lighten the M-240 even further; this entailed replacing the receiver with one made from a titanium/steel alloy, and possibly in the future replacing plastic and polymer parts with ones made from advanced carbon-fiber composites, and even the bipod by one made from titanium/steel alloy. Currently (early 2006), some 20 examples of the titanium/steel receiver version have been procured for testing; designated the M-240E6, they are lighter than the standard M-240B and G models by some 1.81 kg. Target weight reductions for further models call for a total lightening of the weapon by 3.18 kg. It is not known whether this study will lead to a future operational version of the M-240, but the soldiers testing it seem to be enthusiastic about the reductions in weight, and one of the complaints coming out of Iraq and Afghanistan about the standard M-240 is the weight of the weapon. There is a concern that these weight reductions may literally make the M-240 too light for controllability and adjustments may have to be made to the buffer system of the M-240E6 to provide sort of a recoil absorber system. (For that matter, experiments are also being conducted with a lightweight titanium/steel alloy tripod, though this is not covered here.) If they do get fielded, it probably won’t be before 2008 at the earliest.

Twilight 2000 Notes: This weapon did not have much of a chance to be adopted; the Marines only replaced about half of their M-60s with it, and the Army got almost none. The post-2000 M-240 variants do not exist in the Twilight 2000 timeline, nor does the M-240E6 in any version (and in fact, is not even in service in real life as of early 2006).

Notes: US Navy SEAL teams like the light weight of the M-249; they also like the firepower of the MAG (M-240) and its 7.62mm NATO round. What they don’t like is the relatively low hitting power of the 5.56mm NATO round of the SAW, nor do they like the huge size and heavy weight of the M-240. They wanted a blend of the two. They also didn’t like totally like the M-60E3s they were currently using in the role, feeling that the M-60E3 was essentially a compromise what didn’t work out.

FN therefore designed the Mk 48 Mod 0 specifically for them. It is basically an M-249 scaled up to fire the 7.62mm NATO round. (FN had sort of a head-start on this; it’s a little-known fact that the Minimi was originally designed in both 5.56mm NATO and 7.62mm NATO versions.) The SEALs were also given a few other things they asked for in a light machinegun: Teflon coating for resistance to weather and salt water, a little extra weight to keep barrel climb down, a quick-change barrel, and a stronger build. The entire machinegun is, in fact, only a little longer than the M-16 assault rifle.

The Mk 48 Mod 0 is built largely of steel, with some light alloy components, and a polymer pistol grip, stock, and fore-end. It’s rumored that the stock can be replaced with a collapsing one, but I have not been able to confirm this. The standard stock has a shape similar to newer M-249s with fixed stocks, making it somewhat lighter. It uses standard NATO disintegrating-link belts, feeding from the left and ejecting spent rounds through the bottom of the receiver. The Mk 48 Mod 0 can be equipped with a total of five MIL-STD-1913 rails: one atop the receiver/feed cover, three on the fore-end on the bottom and sides, and one over the barrel where it rests on the fore-end. The folding bipod is adjustable for height and cant. The 16.5-inch barrel is tipped with a compact flash suppressor and the bore is hard-chromed, as is the chamber. The standard sights consist of a protected front post and a rear sight similar to that of the MAG, an adjustable aperture rear which may be flipped up to reveal an adjustable leaf.

Though there are rumors of the deployment of the Mk 48 Mod 0 in Kosovo, the first confirmed use was in Afghanistan. The US Army’s Rangers have used it in the recent fighting in Iraq. Though an FN design, the Mk 48 Mod 0 is actually manufactured in FN’s US facilities in South Carolina.

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

Notes: The M-134 is basically an electric Gatling gun, a six-barreled machinegun with an electric motor. Development of these modern "electric Gatling guns" started shortly after World War 2, and the first of these was the famous 20mm M-61 Vulcan series, but early in the US involvement in Vietnam, the Army realized that a scaled-down version of the Vulcan would be wonderful for providing massive volumes of fire when used as helicopter armament. They were first mounted on the various ad hoc UH-1 Huey gunships deployed, and then on the first AH-1 Cobra gunships. Quickly, mounts were designed to allow the M-134 to be used on pintle mounts as helicopter door guns, on patrol boats, in pods on light aircraft and helicopters, and of course, the famous AC-47 "Puff" gunships. The cyclic rate of fire for the original M-134s was originally set at 4000 rpm, and the rotating six-barreled configuration kept the barrels from overheating because each barrel essentially had a much lower rate of fire. Later versions of the M-134 could be set for later rates of fire, ranging from short 10, 50, and 100-round bursts to twin rates of fire of either 3000 or 6000 rpm; this is the rate of fire for most "current: GE-built M-134s, with the burst length essentially controlled by how long the trigger is depressed. (A skilled gunner is capable of squeezing off 100-round bursts, and I’ve even heard of some gunners able to squeeze off bursts as small as 50 rounds when the Minigun is set on its 3000 rpm setting).

The reason I wrote "current" GE-built models because GE no longer builds the original M-134s (they built the last one in 1975) – in fact, parts for original M-134s are not even being made in the US anymore. Some can be procured from countries still making these parts, but as far as I’ve been able to discover, complete M-134s in their original configuration are not being made anywhere anymore, and most countries that still make spare parts will not sell them to civilians or even directly to military forces – a country’s government has to ask for them. Most parts available in the US these days are the result of cannibalization or their being made from scratch in machine shops.

The GE-built M-134 is, as all modern Gatling-type guns, electrically powered from the vehicle in which it is mounted or an external power source; potentially any external power source may be used, from a battery pack to a generator, but it must be able to provide 28-Volt DC or 115-Volt AC power at 260 amps (though sustained fire requires only 130 amps). If the length of an ammunition belt exceeds 1.5 meters in length, an additional electrical motor must be added at the top of the ammunition chute to provide more belt-pulling power. In addition to their use as aircraft, helicopter, and internal vehicle armament, M-134s can be mounted on pintle mounts, used as helicopter door guns (a very common method of use), or even mounted on standard heavy tripods of various sorts, including those designed for use with heavy machineguns such as the M-2HB and Mk-19 automatic grenade launchers. (I even have a picture of three Miniguns on a single ground mount.) Feed may be from either side; belt length is effectively unlimited, but the normal lengths of belt used with manually-operated M-134s are listed below. If special ammunition boxes and feed chutes are used, the M-134 can be fed from unlinked ammunition. The length of each barrel is 22 inches; the barrels are normally parallel, but barrel clamps are available that allow a variable convergence point. Individual barrels are heavy, designed to fire at least 40,000 rounds between failures (some say as much as 100,000 rounds).

However, 1975 was not the end of US M-134 production. US special operations units still loved the Minigun, but theirs were rapidly wearing out by the early 1990s. There were still a lot of M-134s used as door guns, armament on foreign helicopters, and even by some variants of the AC-130. GE was no longer tooled-up to produce the M-134 or its parts, and they were unwilling to re-establish the production line for the Minigun. Parts could be obtained to a certain extent by cannibalization or by buying them from foreign sources, but this essentially reduced the supply of available Miniguns and buying parts from foreign sources was much more expensive than having a domestic supplier. A company in Arizona called Dillon Aero stepped up to the plate, they essentially bought the complete rights to production and sale of the M-134 from GE. At the same time, they took the opportunity to correct a number of small deficiencies with the M-134, as well as simplifying the design and improving its reliability. The result was the M-134D. Externally, the M-134 largely resembles the original M-134; internally, the M-134D is a very different weapon. The original magazine hoppers and feed mechanism have been redesigned to allow slightly greater capacity, eliminate unnecessary parts, and the actual belt feed repositioned to the top so that weight of the belt pull is minimized. A small electrical booster was also added to the feed mechanism, eliminating the need for a separate electrical motor if very long belts or feed chutes are used. A common cause of jamming on the original M-134 was misaligned rounds (especially when unlinked rounds were used); this problem has been eliminated. Spent rounds and duds are ejected from the bottom of the M-134D, where they can be ejected outside of the vehicle or aircraft or collected in an attached container (or simply fall on the ground). A mechanism has been added which essentially spins the barrels backwards for a fraction of a second in the case of a stoppage, in order to eject the stuck round or case. The M-134D uses coatings and other modifications to reduce friction and increase tolerance to dirt. The bolt is strengthened by building it from a nickel-steel alloy instead of standard steel. Further modifications to the M-134D’s bolt helps ensure that the firing pin consistently strikes the primer (another problem with the original M-134). Variable cyclic rate mechanisms have been removed, and the M-134D fires only at 3000 rpm (mostly to stop wasteful ammunition usage). Normally, manually-fired M-134Ds have no sights (aim is to be corrected by tracers), but sights can be added. The amount of possible mountings for the M-134D (and other Dillon M-134s) are so vast that they cannot all be mentioned here; they have even modified a Chevy Suburban to fire a Dillon M-134 out of the rear!

Dillon has recently designed a new version of the M-134D, called the M-134D-T. Designed to reduce weight, the M-134D-T uses some skeletonized components where possible, but most of the weight reduction has come from replacing the rotor, housing, parts of the feed mechanism, and the barrel clamp/flash suppressor with versions made from titanium instead of steel.

In all cases, Dillon Miniguns can be had with three lengths of barrels: the standard 22-inch barrel, a heavy 22-inch barrel, and a short 18-inch barrel. Currently, Dillon does not built tripods or soft mounts for their Miniguns, but they can still use M-2HB tripods and soft mounts, as well as a large amount of pintle mounts, internal aircraft and helicopter mounts, pods, internal and pintle vehicle mounts, boat and ship mounts, and even on mounts like the new remote weapons stations. It has even been used successfully with some of the experimental combat robots DARPA is testing. Dillon also offers rebuild kits to convert existing M-134s to the M-134D or M-134D-T specifications.

Statistics below are for Miniguns mounted designed for mounting on tripods or pintle mounts; Miniguns designed for internal vehicular, helicopter, or aircraft use are typically 4-6 kilograms lighter (depending upon the installation type). The weight includes a typical power source and electrical motors (but, as usual, not a tripod).

Twilight 2000 Notes: M-134D development and production was dramatically ramped up prior to the Twilight War; in addition, Dillon agreed to make spare parts for older M-134s in addition to making conversion kits. The M-134D-T does not exist in the Twilight 2000 timeline.

*These weapons cannot be fired without a tripod, pintle, pod, or internal aircraft or vehicular mount.

**The rate of fire of these weapons is so high that squeezing off single shots is impossible, even for highly-skilled gunners.

Notes: The M-85 is a heavy machinegun designed for coaxial and cupola use; it equipped the commander’s cupolas of the M-60 series of tanks and the AAPV-7, amongst other vehicles. Though still found on the AAPV-7 series and such older vehicles, it has largely been withdrawn from service in the US and in most other countries.

The M-85 is a recoil-operated machinegun fed by standard .50 BMG disintegrating link belts. Cocking is done by pulling back on handles on either side of the gun (connected by chains to the gun). It is normally used on vehicles, and is in that case fired by solenoid connected to a firing switch (with a hand trigger backup). It can also be mounted on a standard M-2HB tripod and fired from it, but in actual practice this was quite rare. The M-85 has a dual rate of fire; normally, the gun is kept at the ground target cyclic rate of 400 RPM, but it can also be switched to a ROF of 1050 RPM for use against aircraft or a large amount of targets. The fire selector is a dial-type on the rear of the gun. No provision is made for semiautomatic fire, but when set for the lower ROF, single shots or short burst are easily squeezed off. The barrel length is 36 inches, and the muzzle is tipped by a large flash suppressor. No sights or sight mounts are provided, since its primary use is as a vehicle weapon.

General Dynamics GAU-19/A

Notes: This is an electrically driven .50 caliber Gatling gun, capable of delivering a massive volume of large-caliber fire. An optional gas drive may be added if external power is undesirable, and the GAU-19 can also be driven from an air compressor. It can fire both linked and linkless rounds. The GAU-19/A originally was tested using 6-barrel and 3-barrel configurations; the 6-barrel versions unfortunately were rejected due to high ammunition consumption, greater weight, and high electrical energy consumption.  For a while, it looked like the GAU-19/A was going to be rejected in any form (it's been around since the late 1980s), but special operations troops gave it high marks in Afghanistan and Iraq, and it is now being issued as a "tail gun" on heavy-lift special operations helicopters.

Twilight 2000 Notes: The GAU-19 is made in a 3-barrel short version and a 6-barrel long version. The 6-barreled version is very rare.

Notes: As implied by the name, this is an improved, light version of the Browning M-2HB. In addition to a QCB barrel, the RAMO Lightweight M-2 uses a shorter, lighter barrel, an adjustable rate of fire, and some lighter components. However, 75% of the parts of this weapon are interchangeable with the standard Browning M-2HB.

Twilight 2000 Notes: This weapon exists only in very small numbers.

Notes: This is one of several upgraded versions of the M-2HB. Improvements include an adjustable fire rate (from 500 to 750 rounds per minute), while retaining the semiautomatic fire capability. The receiver has been strengthened by replacing most of the riveted construction with welding; this has also lightened the weapon. The charging handle is much easier to pull back than on the standard M-2HB. Most importantly, the need for the tedious headspace and timing adjustments of the standard M-2HB have been eliminated, making the weapon easier to maintain and more reliable. There is a short muzzle break on the end of the barrel.

Notes: The M-207 was the only version of the Stoner officially type-standardized by the US Army, and was also used by the Navy. It is basically a larger version of the Stoner 63A series that uses a longer barrel, belt-feed exclusively, and extra rails for vision equipment. It has a provision for mounting on a tripod. It is perhaps easier to find these days than other members of the family, but is still a museum or collector’s piece.

Twilight 2000 Notes: As with other members of the M-63A family, improved versions showed up in the hands of SEALs and Marines during the Twilight War.