A Blog Devoted to Exploring and Explaining the World of Military Science Fiction.
18 August 2012
FWS Armory: The Light Machine Gun
When your troops are moving up, the soldier behind them is tasked with forcing the enemy to keep their heads down with covering fire, from the portable machine gun. This is the basic infantry tactic since the First World War, and today, the light machine gun (LMG) is a critical tool of modern warfare used the world over. However, it seems that science fiction has not gotten the memo, and LMGs remain one of the most forgotten elements of basic infantry combat in military science fiction stories. FWS will be exploring the LMG through its history, usage, its future, and sci-fi's take on the LMG. Also, FWS would like to thank William S. Frisbee Jr.'s Tips on Writing Military Sci-Fi website for the general information on machine guns.
What are Light Machine Guns and their combat role?
Since World War One, the Light machine guns have allowed small infantry units to have a portable primary weapon for providing support-by-fire for the squad, pinning down the enemy, and allowing the infantry to close in on the enemy. These weapons are belted or magazine fed and normally use the same cartridge as the assault rifle. In combat, the machine gun forms the defensive or offensive backbone of any operation, by providing covering fire via large volume of outgoing fire.
The History of the Light Machine Guns
Since the 3rd century, mankind has been attempting to develop a portable rapid-fire weapon that could crush multiple enemies on the battlefield. At first, there were industrial arrow launchers from the Roman Empire, then became the so-called 'organ-gun' or the Ribauldequin of the 13rd century, where a row of barrels were mounted to a cart to act as a volley artillery gun, and even Da Vinci had his fan-gun. However, this were not truly portable or even effective, due to accuracy and reloading times. A number of different designs were based on this basic principle of volley-fire and used for several hundred years.
The next evolution of the machine gun came with the development of the Puckle Gun in 1718 by James Puckle, that was a hand-cracked, tripod-mounted, single barreled flintlock rifle that featured a cylinder-feeding system, limited the Puckle Gun to 11 rounds. However, if there were ample cylinders pre-loaded, it could act as an support or heavy-fire weapon. The more unique feature of the Puckle Gun was that the cylinder could fire round or square bullets depending on the religion of the attackers. More 'humane' round bullets for the Christians and the savage square bullets for the heretics and Muslims (especially Turks). It was reasoned that more Turks would convert to Christian rather than suffer from square-bullet wounds. Conversation through gun-shot wounds, an interesting approach to religious conversion.
During the 19th century, guns like the Agar Gun also known as the coffee mill gun of the American Civil War, and the Mitrailleuse gun of the 1850's that mounted a 25-barreled, hand-crack operated 13mm rifle to a cart, making the Mitrailleuse gun a portable rapid-fire weapon system were little more than variants of the grape-shot artillery round. The Mitratilleuse gun was improved over its 40 year lifespan to include 37 barrels, and saw limited use in the Frano-Prussian War. Despite lack of service life, the Mitrailleuse gun may have been the first rapid-fire gun to carry the name "machine-gun. What killed the Mitrailleuse gun from became a world-standard, was the American Gatling gun.
Oddly, Dr. Gatling envisioned his repeater to so effective, it could end future wars...yeah, that didn't happen. Oddly, even after the Union Army got a demonstration, they were unimpressed despite the current situation with the Civil War, and that nothing existed like the Gatling Gun at that time. One of the issues was the vast amount of calibers used in the Union Army, the Gatling Gun was just another weapon to feed, and it was a large, heavy weapon (around 1,000lbs) that did not have the range of an artillery piece, and it was too new. The few that were used during the Civil War were mostly defensive, and most historians do not think it made much of a difference. However, it was a hit on the international market, and used by the US Army during the Indian Wars, but not at the Little Big Horn. During the British imperial expansion, the naval and land based Gatling Guns were used to suppress native tribes, especially in the Zulu Wars.
But all of these rapid-fire guns were man-operated, it was not until the 1884, that the first true machine gun was developed by Hiram Maxim after a shooting trip, when he wondered if the recoil energy could be used to power the gun's reloading mechanism. This rapid fire weapon that fed from a belted system and featured the distinctive water jacket to cool the barrel became a global success, and soon was fielded in imperial suppression of native tribes operations by European nations. Most believe that the machine gun was first used in the muddy fields of World War One, however, it is believed to be first used in combat during the 1st Matable War in 1893-1894, with the British in Rhodesia. The first large-scale conflict that witnessed the use of the machine gun was the British version of the Maxim, the Vickers (in the .303), was used in the Second Boer War (1899-1902). Not only were the Maxim Gun devastating against the old style of infantry warfare were soldiers lined up and exchanged fire, but it had a crushing effect on the will of the soldier. However, it was not all roses, sunshine, and spent brass, the Maxim gun jammed during combat, and made great amounts of smoke from being fired. When the accuracy failed to kill the enemy, the mere slight and sound of machine gun fire, drove the enemy from the battlefield. The greatest American arms marker, John Browning, developed his own lighter, air-cooled, machine gun in the .30-06 caliber, the M1895 Colt-Browning, also known as the 'potato-digger', due to its underslung swinging leveler action. While it was used by the US military for a limited time during the Spanish-American War, it was later replaced by a Maxim machine gun made by Colt. But, one critical element was missing of these early MGs: portability. Machine guns of this era were only portable by a team or even an animal, and required a several soldiers to operate them. The machinery also suffered from the use of rifle-sized calibers that increasing the recoil and wore on the machinery. The first military light machine gun was the 1902 Danish Madsen LMG that fed from a box-magazine on the top of the weapon, similar to the British Bren LMG, but was mostly limited to its home nation. For widespread adoption of the LMG into most military organization to take hold, would take the brutal combat of World War One.
Machine guns of the First World War were mostly emplaced and difficult to move, often used in defensive and support roles, but reaped heavy tolls on attacking soldiers, often bleeding the ground red. When soldiers on the western front were able to capture an enemy's trench line, they were left to defend it with only what they could carry across no-man's land. That gave rise to weapons like the CSRG M1915 automatic rifle, or the Chauchat. This odd looking weapon fired both the French 8x15mm and American .30-06 round via an exposed crescent shaped magazine, and featured vertical hand grips and a built-in bipod. Given the lightweight, the Chauchat was easily carried into battle, supporting the assault from trench to trench, and was one the only LMGs on the battlefields of Europe.
This caused the American Expedition Force of 1917 to hastily adopt the French made gun due to lack of arms available at the beginning of the American involvement, but was replaced by the excellent BAR in 1918 at the closing months of the war. Many historians considered the Chauchat the worst weapon forced on the US serviceman, given its design and open magazine, the weapon was prone to jamming, poor build quality meant that parts from one Chauchat were not interchangeable to another.
Unlike the unlucky that were forced to use the substandard Chauchat, the British had their own LMG for the western front, the .303 Lewis Gun. This weapon was air-cooled, fed from a disc-like magazine on the top of the weapon, and was easily portable on the uneven conditions. This weapon would see action in the skies as well as World War II battlefields, while the Chauchat was rusting in a landfill.
Portable infantry-based machine guns would become a staple of ground combat in the Second World War with weapons like the BAR, the M1919 Browning Machine gun, and the German's MG42. World War II was the test of how the machine gun would incorporate itself into modern warfare, weapons like the BAR proved the concept of the LMG, but were limited by weight and small magazine capacity (the BAR only held 20 .30-06 rounds), then we had more traditional machine guns, the M1919 and MG42 for example, that offered more firepower to suppress the target(s), but required a team to set them up and hump them across the battlefield. What was needed was a weapon with the portable of the BAR, but the effectiveness of the MG42.
By the time of the Vietnam War, the light machine gun was an fully integrated element into infantry combat. Weapons like the American M60 and the Russian PK were pitted against each other in the dense hot jungles of Vietnam, one was a child of AK designer Mikhail Kalahnikov, and the other was based off of the MG42. While both survived the war, problems were noticed, namely the weight of the gun itself and the ammunition. Recently, I was at gun store in Fort Worth that is a Class-III firearms dealer, and they happened to have to an M60 in their safe. For kicks, I asked them to get it out, and it was unbelievably heavy, and that was unloaded, with me wearing tons of tactical gear. This reason led firearms markers to design LMGs around smaller rounds, like 5.56mm, and the standard assault rifles, with weapons like the H&K H21,and the RPK. By the 1970's, countries were starting to field these new lighter LMGs, but now where calling them 'squad automatic weapon' or SAW, which were often belt-feed lighter weight machine guns that fired the same cartridge as their standard assault rifle. In addition to these LMG, came the ones based around assault rifles, the family concept, like the Steyr AUG LMG, and the Stoner 63 used by the SEALs in Vietnam (there is a Knight Armament upgrade version). During the twin wars in Iraq and A-Stan, the standard US LMG, the SAW, has been cut down to compact variants like the para, which is now lose in size to an assault rifle, finally becoming a truly portable all-conditions soldier's machine gun.
Light MG vs. Heavy MG vs. General Purpose MG
Machine gun is a blanket term that can mean (especially in the media) any kind of fully automatic weapon. However, for most military and gamer use, a machine gun is a weapon designed to put maximum rounds down range with heavier volumes of fire, and encompasses three different types of MGs, the light, general purpose, and the heavy. Light machine guns are generally magazine or belt fed portable machine guns used in infantry combat, firing a general assault rifle cartridge. In the middle of the light and heavy machine guns, is the general purpose machine gun (GPMG), which general is a belt-fed machine gun is used in a number of roles, from traditional infantry, to a door gun, vehicle mounted, or gun emplacement, an American M60, German MG42, or the Russian PK are good examples of the general purpose MG.
While the light machine guns and the general purpose are more similar, the heavy machine gun is completely different animal that fires larger round that is above 12mm and below 20mm. These are often used in anti-aircraft roles along with mounted heavy fire support. Good examples are the 12mm Browning M2 and the Russian DShk. When machine guns reach the 20mm and above category, they are considered auto-cannons, like the US XM307 25mm crew-served weapon. The Machine Gun Team
During World War I and II, machine guns were treated more like mobile artillery, often emplaced and non-mobile, the infantry, often sucked up as many as four to six soldiers to service one machine gun (especially WWI). There were soldiers to load the weapon, to replace the barrels or fill the water-cool sleeve, one to command, and several to provide security. Today, while not as common as it used to be, machine gun teams still exist, though mostly called weapons teams, now, and normally use the heavier weapons available to the unit. Today's light machine guns are assigned several to a squad of soldiers, with several soldier being designated to either be a backup gunner or carry extra ammunition.
During Vietnam, it was common for every member of the squad humping about 100-to-200 rounds of belted ammo to support the heavy amounts of fire. No more are LMGs static devices on the battlefield, but are in the middle of the action. with the LMG being lighter and more compact, gunners are able to be in the middle of the action, able to support the team.
The machine gun operator will be armed with a sidearm or a PDW for their own protection, however, there should be several soldiers armed with assault rifles, assigned to the gunner as security. It should be noted that the critical role of the MG Team makes them a target for any attacking force, and one of the worst times to use a LMG is at night due to the muzzle flash, night blinding the operators, and exposing the MGs position. Machine gun teams were featured in Star Wars: The Empire Strikes Back, when the stormtroopers stormed Hoth, set up E-Web repeaters which require a exterior cooling cryo-unit and a generator.
Machine Gun Terminology
Grazing Fire- LMG is placed on an area one-to-four feet off of the ground
Final Protection Fires- When the enemy is about overrun the position, and the MG teams are used for preventing the position being overrun as long as possible
Final Protection Line- Interlocking MG fire from weapons on the front-lines. Wall of Lead.
Beaten Zone- Where the rounds from a MG fall
Cone of Fire- The path of the outgoing rounds impacted by the recoil of the gun
Plunging Fire- when MGs are fired from uneven territory
Traverse & Elevation (T&E)-
Frontal Fire- The MG team is faced directly at the enemy, which opens up the MG Team open to incoming fire from the enemy.
Flanking Fire- The MG team is directing fire at the sides of the enemy, one of the better positions to be in during combat.
Oblique Fire- When the MG Team is putting fire down on the enemy at an angle
Enfilade Fire-When the enemy is one prefect follow-the-leader-line, and one bullet could pass through them end-to-end. According to one website, the is a machine gunner's wet dream.
The Future of LMGs
For those of us that have even held an LMG, can only imagine humping one over miles and hours, with the weight of the gun, attachments, and ammo-box. When the shit hits, the LMG, while extremely useful, can be a handful in maneuverability and weight, especially in close quarters conditions. Being aware of this, the US military is attempting to develop an light machine gun similar in size and weight to a normal assault rifle, oddly going back more to the original US military LMG, the BAR in some ways. The weapon that is being tested is the lightweight small arms technology light machine gun, the LSAT LMG. In 2004, the US military proposed that arms makers field a lightweight machine gun and ammunition. AAI Corporation, a division of Textron (who my uncle-in-law works for), turned a prototype in 2004 that had been designed with computer simulations, lowering the weight of the LMG down by 43% of the standard SAW.
Adding to the weight-reduction, while still maintaining the same operating systems as the SAW, was lower-weight ammunition. AAI tested two versions of the LSAT LMG, one firing a caseless bullet, the first tested by the US Military since the 1980's, and the other using a polymer-cased ammunition. The results were promised when the prototypes were tested by 20 US servicemen against the Mk.46 SAW in 2011, As of this blogpost, the LSAT LMG fate is unsettled, some believed that the project will being viewed as a testbed of advancing firearms technology, and new types of ammunition, like the telescoped and caseless. For the time being, the role LMGs will likely be same, servicing as the defensive and offensive power in a small infantry unit, and it is unlikely that there will be an great changes unless the USMC approved caseless ammo for their LMG project. In the last few years, there has been improvement with recoil damping technology, allowing for greater accuracy, and lower the weight, and continue to feed from either belts or magazines.
Much like assault rifles, LMGs will feature attachment rails for all manner of goodies, and sport bipods, however, some article point to experimental technology of computerized aiming systems, like the ALIENS Smart Gun. With the family-style weapon systems being popular, trend of LMGs being based on an assault rifle base, and even some will be a bullpup design. It is possible that in the near future, LMGs will use caseless ammunition in cassettes or even helical drums for faster reloads and greater ammunition capacity than typical magazine-fed LMGs, and likely grow lighter in weight and more compact. This exploration of caseless ammo for an LMG makes sense, the prototype of the G11 light machine gun would have 300 rounds of 4.73x33 in a single cassette, making for lightning reloads. I can imagine caseless LMGs being a possible over the traditional assault rifle.
Future Military Applications of LMGs I developed this section of certain blogpost to help writers of MSF with incorporating certain concepts into the future world of combat, and this one is easy. Even when we reach the stars, and fight among them, there will still be a support weapon, and no serious military science fiction work that depicts infantry combat should not be lacking in a LMG type weapon. The fact is that infantry units, like today, will operate in remote off-world conditions, where the only heavy fire support available immediately could be the light machine gun or something equal. For your future squad of badass marines to be believable, than they need to have some machine gunners, even if it fires plasma, laser death rays, or high velocity hockey pucks, there needs to be a support weapon. And please for the love of the Lords of Kobol, don't follow the Killzone example and mount a frakking rocket launcher underslung to your machine gun!
Feeding Systems -Belt Fed
The majority of LMGs used to today, are akin to their heavier cousins by use of linked or belted ammunition. Belt-fed LMGs are the preferred method due to larger capacity of ammunition, longer rates-of-fire, and less jamming over magazine-fed LMGs. Originally, these belt-fed systems were made of canvas, allowing these belts to be reloaded. Unlike, those early versions of linked ammo, today's links break apart once the round is ejected, but the ammunition has to be manufactured has linked, causing most members of a squad to carry extra linked ammo, adding to their loads. Currently, the US is experimenting with backpack-fed systems...Predator anyone? -Magazine Fed
Less popular, is the method of feeding ammunition from drum or the beta-c magazines., in either traditional layout, or bullpup configuration. These are mostly used on the LMG variants of the 'family-style' assault rifle systems, like the SCAR, XM8, and the G36. Some believe that these are the most portable form of the LMG, and the easiest for soldiers to use, due to the similar to the base assault rifle. However, jamming is a disadvantage of magazine-fed LMGs along with added weight, and less-capacity, where most mag-fed are 100 rounds, and belt-fed are 200 rounds. -Cassette Fed
During the development of the G11 caseless rifle for the West German Army, Heckler and Koch created two variants of the main weapon, the G11 PDW pistol and the LMG. H&K envisioned an LMG weighting in at less than 7kgs with a box of 300 4.73x33mm caseless rounds. In the few pieces of information we have on the LMG variant of the G11, it would have loaded via a cassette box at the rear, making it a semi-bull pup rifle, then snapping it close, becoming the stock of the weapon. This loading operation was very quick, making the LMG11 one of the fastest reloads on an LMG in the business. In addition to fast reloads, the cassette was lighter than a box of 5.56mm, and easily to haul around as well. Cassette fed LMGs could be a better system that the more tradition systems mentioned above, and could led governments to adopt caseless weapons in LMGs only.
Unfortunately there is little information on the LMG11, including if there was a firing prototype. David, one of the consults to FWS, recalled that there was a string running through the caseless ammo, to act as a belt, feeding the rounds, and this string came out the forward section of the weapon.
Directed-Energy Portable Multi-Pulse Support Weapon
In the future, science fiction informs us that we will all being ray-guns that create death via killer light on future battlefields. Is it possible for there to be a directed energy version of the light machine gun, or as David, one of the consults to FWS, called it: 'directed-energy portable multi-pulse support weapon'? It is likely that normal infantry DEW rifles would be a slower rate-of-fire, requiring an heavy infantry support weapon akin to the LMG role, but they would not be similar in performance.Unlike those lead throwers, lasers would be unable to pepper an area with out-going fire, lasers by nature are a beam of light, causing the laser support gunner to operate the DEW differently than the classic machine-gun, bouncing the beam from target-to-target. Another consideration, is that bullets are a self-contained kinetic energy delivery system, lasers and particle beams, to a lesser extent, relay on dwelling time for damage to the target. That is, unless you pump up the energy output to a level were you're burning 6cm hole that is about 30cm deep each time the pulse-beam strikes the tango. Then you have to worry about power consumption and heat. This could mean that DEW support weapons would similar to the E-Web from Star Wars, where the gun is hooked into a cryo-plant and power generator, needing a crew to haul the thing around and serve it.
One of the best features of a laser support system is instant impact, and immediate psychological results on the rest of the squad not hit by the beam. The two major issues facing deployment of a support laser is cooling and power source. Much like with LMGs today, everyone in the squad would carry power packs for the support laser, and it is possible of development of 'thermal clips' similar to the ones in Mass Effect.
Sadly, lasers or charged particle beam portable DEW systems are beyond our science, while we have vehicle mounted defensive laser emitters, we have nothing that Flash could strip on to his back.
Here is the short list of the needed upgrades to a base laser DEW rifle to be an DEPMPSW:
larger power/fuel cell source
improved cooling system
longer beam firing time
Light Machine Guns and Science Fiction
If you ask any modern soldier going into battle, if s/he would kindly leave their light machine gun behind, you'll get a 'fuck you' in response. But that is what most science fiction creators are doing when they send their fictional soldiers out into future battlefields without an LMG to support them. But why? Why would a weapon as critical as the LMG get overlooked by science fiction? I would guess that sci-fi creators do not dwell hard enough on the reality of war and infantry tactics, and believe that an assault rifle is good enough. Or they somehow believe that futuristic laser-blasters will overcome the basic need for an LMG.
Anyway, Light Machine Guns in are extremely rare in all types of sci-fi works, however, they are more common in shooter sci-fi video games. This is likely because of the need from world of multiplayer, and after all, if Call of Duty has it, shouldn't that game have it as well. They become even rarer when we further discuss LMGs that fire directed energy beams or bolts, making the Light Machine Gun one of the most forgotten elements of small unit combat infantry in science fiction or. Hell, even the best examples of MSF, like HALO, Space: Above and Beyond, the Forever War, and Old Man's War, all lack this basic weapon of infantry combat that has been in use since World War One.
The M56 10mm caseless 'Smart Gun' from ALIENS
One of the few great examples of a future LMG is the Colonial Marines M56 'Smart-Gun' that fires a higher power caseless 10x28mm round than the M309 in the M41 pulse rifle. According to the 1996 ALIENS: Colonial Marines Technical Manual, the smart label is in reference to the M56's computerized IR tracking system, that allows for some quirky behavior by the gun's computer system, sometimes it nails each round into a tight group and other times, it is throw way off, causing the marines to switch off the IR tracking system. In order to allow maximum effectiveness, the M56 was fitted with twin firing triggers. One is at the rear of the weapon, while the second on the horizontal grip, along with the fire sector and fuse timer switch. Powering the electronic pulse ignitor for the caseless propellant is a DV9 battery, which is seen in ALIENS when Sgt.Apone asks for magazines, Drake and Vasquez hand him the batteries and not the ammo drum. This confused a great deal of us fans prior to the release of the ALIENS: Colonial Marine Technical Manual, some believed that the Smart Gun was a DEW or that it fired some sort of exotic ammunition.
The prop for the Smart Gun was developed from the MG42 (of course), fitted with a few motorcycle parts, and a drum magazine, and attached to the actors via a steady cam harness to prevent them from falling over, due to the weight. The original concept for the Smart Gun was to have the actors wear a flux power-glove concept instead of the harness.
The M247H from HALO: Reach
Throughout most of the HALO games, it appears that UNSC does not use an LMG to support their troops, nor does the aliens. Most of the UNSC heavy weapons support comes from the Warthog's tru-barreled 12.7mm rotary cannon. There are a few times, when a emplaced M247H is used to defend an area, especially during the Earth portions of HALO 2. According the HALO wiki page, the M274H machine gun is listed has a 'heavy' machine gun for some strangle reason, despite firing the same 7.62x51mm round as most of the UNSC small arms. However, it used by Jorge-052, detached as an LMG for the Noble Team.
The M739 SAW from HALO 4
It seems that the Lords of Kobol have blessed us, in November we're getting more HALO and that the UNSC is finally fielding a proper LMG: the M739 SAW. When it was original featured in the HALO Waypoint UNSC weapons trailer, I believe that it was some sort of auto-shotgun due to the drum magazine, and that would be sweet running down Grunts with an auto-shotgun, but I'll take this SAW. No word if it fires the same 7.62x51mm round has the MA5B assault fire.
The Repeater Blaster from Star Wars
I am always impressed with the variety of DEW systems in the Star Wars universe, and that includes some rare examples of DEW LMGs, but they are repeater blasters in a galaxy far, far away. According to a few sources, there are two kinds of portable repeater blasters that fit the LMG/GP category, the mounted version seen during the Battle of Holt used by the Rebel Alliance infantry (believed based on the American WWII-era .30 machine gun), and the handheld T-21 light repeating blaster rifle seen in SW:ANH in the hands of Stormtroopers at Mos Eisley. Normally, the T-21 has only enough powerpack capacity for thirty shots, however, most troopers carry an powerpack backpack that weights in at 60lbs. Ouch! The base gun for the T-21 LRBR prop was based on the British .303 Lewis Machine Gun
Heavy Bolter from Warhammer: 40K It seems everything in the Warhammer 40k universe is bigger, and that applies to their version of the LMG. In the ranks of the Space Marine, only these genetically engineered armor power suit wear soldiers are able to wield the heavy bolter that unleashes .72 caliber rounds at fully automatic fire crushing the enemy. From my older codexs (1998), only Space Marines can use the heavy bolter due to its massive recoil and weight. I've seen modelers use the heavy bolter as a heavy machine gun for the Imperial Guard troopers, similar to Browning M2 .50 caliber, The Helghast StA-3 LMG Killzone
In the first two Killzone games, the Helghast troops use a futuristic take on the old 3rd Reich MG42, the StA-3 LMG. Much like the assault rifle, the StA-3 feeds from a translucent drum magazine prepackaged with bullets. From the wiki, it lists the StA-3 firing the 7.62x51mm round, and in the game, you can see spent brass flying off, but I think the Helghast weapons fire a smaller round than 7.62mm NATO...maybe the Russian 5.45x39mm round?Anyway, this is one of the best all round guns in the original PS2 Killzone, and damn fun online, allowing the player to really hose that thing! Some have charged Guerrilla Games with lifting the basic idea for the Helghast soldiers from the Jin-Roh: the Wolf Bridge OVA, based the Panzer Corps uses handheld MG42s and similar armor design to the the Helghast soldiers.
The GD RSB-80 Heavy Plasma Gun from the Terminator
In the original Terminator, an infiltration unit sneaks in with some refugees to the bunker complex of the 132nd, "and the bunker was seared with light." The gun that devastated the bunker was the General Dynamics RSB-80 that fires a 15x1000mm plasma bolt with a capacity of 300 pulses at 60 pulses-per-minute from the slush hydrogen tank. In the hands of the Terminator, the RSB-80 becomes an awesome tool of destruction, and unitized as an LMG. However, the weapon is too heavy for an average Resistance fighter to hand-carry, instead, it becomes a general purpose DEW LMG, mostly mounted to technicals and as an emplaced weapons for area defense. IMFDB.org has been unable to identify the base gun of the prop, but it is mostly likely a WWII-era Lewis MG. One the best fan-site for the dark world of 2029 AD, there is information on a heavy phased plasma gun: the General Dynamics RSB-80. The RSB-80 HPG was only seen on-screen twice, once for a few seconds during the Sarah Conner's dream sequence, and when Kyle blows up the H&K tank, and attempts an E&E with a junker armed with a RSB-80.
Article on the RSB-80: http://www.goingfaster.com/term2029/rsb80.html
The MG42 From Jin-Roh: the Wolf Bridge In the alternate future of this iconic Japanese OVA, the Panzer Corps, members of an elite anti-terrorist squad of the Japanese police department use the 3rd Reich MG-42 (and STG-44) to hunt down and destroy the Sect terrorists. These armored soldiers are able to do this via the protection gear and a specially designed belt-ammo feeding system.
Starship Troopers (Uchu No Senshi) Anime OVA (1988) Unlike a great deal of stories with armored power suit donning infantry, the 1988 anime OVA adaptions of Starship Troopers, features a mix-weapon squad, complete with an machine gun based around the MG42 7.62mm machine gun.
The AVR-30 from AVATAR
Much like other sci-fi weapons, the AVR-30 is a plastic-fanatic redress of the old M60 general purpose machine gun, and it seems that the AVR-30 is used in a similar role. The weapon is seen being used by Jake and Norm in their avatar bodies, and appears more like an assault rifle. Interestingly, the AVR-30 uses belted traditional ammunition, while most of the small arms in AVATAR are caseless. Most of the RDA contractors on the ground use a LMG variant of the CARB caseless rifle.
The Steyr-Phoenix Arms AHL-1 Heavy Laser from Empty Places In my last flash-fiction serial for this blog, Empty Places, conscripted soldiers from a post-nuclear Apocalypse are send into battle to defend Earth colonies that abandoned Earth after the nuclear exchange. These armored encased soldiers use laser DEW from Steyr-Phoenix Arms, including the AHL-1 heavy laser.This, like all DEW weapons seen in Empty Places, where developed by FWS reader Christoper Phoenix, and could be the most scientifically explained DEW LMG in sci-fi. Firing 10jJ antipersonnel bluish laser beam in the frequency of 500nm-0.5 microns from a 20 MJ super-conducting coil battery, enough for about 2,000 rounds. Due to the size and weight of the SRA AHL-1, it was used by Colonial soldiers in standard issue powered body armor.