The first machine guns were utilized like light artillery, weapons akin to the regimental Infantry guns.
During World War One weapons like the Lewis gun made it possible for the machine gun to be used at squad level. Most nations adopted light machine guns (1) chambered in the same rounds as their service rifles.
The US followed a slightly different path. The US army had adopted the French idea of "Assault by the walk". The idea was that each infantryman would plod across no-man's land, each spraying the enemy trenches with his personal automatic weapon. One of the weapons intended for this task was the Browning Automatic Rifle (BAR). Luckily the war ended before "Assault by the Walk" could be tried for real, but the BAR was retained in service, but now as a squad automatic. The BAR served in this role for many years, but it was not without its shortcomings. The BAR had not been designed to be an LMG, and simply putting a bipod on it didn't make it one.
The eve of World War two brought a new innovation. The Germans were already using belt fed light machine guns, and someone asked the question whether the same gun could serve in the role of both a light and a medium machine gun? The MG34 and the later MG42 proved the answer to be a resounding "Yes".
Contemporary accounts mention that German infantry seldom bothered to use their rifles, the fire of the squad machine gun usually being more than enough.
After the war most nations adopted some form of "General Purpose Machine Gun". The weight of the GPMG was similar to the LMGs already in use, but was more versatile and offered the advantages of belt feed.
Things got interesting when many armies adopted intermediate power rounds for their rifles. Many people theorized that the squad's machine guns should be of the same chambering as its rifles, so there was a renaissance of light machine guns, this time in intermediate chamberings.
The design group for the US XM732 squad automatic weapon had a different approach. They felt the infantry needed a lighter weapon but planned to chamber it for a new round not used by either the squad's rifles or GPMG. (2)
It was not until the adoption of the FN Minimi (M249) several decades later that the US was to have an intermediate round LMG. In fact the M249 is the first true LMG to ever enter general service with US forces! (3) Some confusion was caused here. The GPMG was already being referred to as an LMG when used in the squad role, so the M249 light machine gun was designated SAW (Squad Automatic Weapon). This has caused some American writers to labour under the misperception that all LMGs use a more powerful round than rifles and that LMG and SAW are different weapons. In fact one describes form, the other function. (4)
Theoretically, a modern infantry squad is armed with rifles and LMG/SAWs, all chambered with the same round.
But a strange thing happens when a shooting war comes along. Any available GPMG gets pulled out of the armoury and begins to reappear as squad level armament. It seems that when the bullets are real, soldiers bitch less about the extra weight of the GPMG and remember how it can hit harder and further.
Not only does a GPMG improve the defensive and offensive firepower of an individual squad, it also enhances the squad's capability to support other squads in the platoon. Some German Panzer Grenadier rifle squads carried not one, but two MG42s. Rhodesian Fireforce units often carried two FN MAG GPMGs in a four man unit. The German Platoon headquarters section was usually less than squad strength, but often included a two man MG42 team in addition to any weapons held by the rifle squads.
Intermediate calibre LMGs like the Minimi and RPK are a useful addition to a fire team, and a useful asset for small units engaged in medium-range very mobile operations such as MOUT, scouting and jungle warfare. However, the GPMG is unlikely to disappear as a squad level weapon anytime in the near future.
Many of the GPMG designs in use are several decades old, and it may be time to examine if they can be made more effective.
More recent models of GPMG like the Vektor SS-77 (5) have managed to shave a few pounds off the weapon's weight. It's possible that for squad use the weapon could be made handier with a shortened "Assault barrel" without reducing the performance significantly. At 18.5 lbs and 39.5 inches overall length the Mk 48 has continued this trend.
More important than weight is the weapon's ergonomics. Weapons like the MG34 and MG42 were heavy but well balanced, so firing from the hip was an effective option.
Improved methods of carrying ammunition should also be considered. The under-receiver boxes used by the M249 could also be constructed for GPMGs.
Squad GPMGs are also one of the most likely weapons to make use of Gun-shields. These should be located just ahead of the barrel change handle, and a horizontal cut-out provided in the shield to allow barrel removal. When in action this opening may be covered by a smaller shield cliped to the barrel. A handle on the back of the shield can help the gunner support the weapon, and feet on the bottom of the shield may remove the need for a bipod. Graticles etched on the surface of the transparent shield material can assist in range estimation.
An interesting criticism that I've encountered is that GPMGs are not as effective as true MMGs in the sustained fire role. This seems to depend on the model used the German army seems to have had no problems.
The South Africans do still manufacture true MMGs (a copy of the Browning M1919) and it could be argued that the 7.62mm Gatling mini-guns are a form of medium machine gun. A friend suggests the idea of a MG chambered in .338 magnum as a vehicle weapon and true medium machine gun.
In most armies, however, the bulk of sustained fire will still be down to GPMGs. The obvious way to improve things is to make sure that each weapon has an adequate supply of spare barrels. Hot barrels should be positioned so there is a good circulation of air around them.
Stickers with thermo-reactive dyes (such as are used in children's thermometers and on fish tanks) would allow the crew to determine the temperature of a barrel at a glance.
For sustained fire, there may be merit in issuing extra-heavy fluted barrels. The weight of these will improve long-range accuracy.
Alternately, there is no real reason why a barrel with a water jacket could not be issued.(6) The machine guns used by the support company of 1944 US infantry battalions were often water-cooled M1917s, rather than the air-cooled M1919s held at rifle company level. Desirable features from water-cooled machine guns of the past include steam condensers and large diameter filling caps, as used on Russian Maxims. Inevitably the hot water will be used to warm MREs! -no reason the condensor couldn't have an MRE heating compartment, even a heat exchanger with potable water so you can brew up (you can spot I'm a Brit!). During the First World War watercooled Vickers machine guns on many instances are known to have fired 10,000 rounds per hour, for periods of up to 12 hours. The sights of such weapons often included compasses, allowing them to be fired to a set bearing.
Laser rangefinders and optical devices obviously have a place on modern GPMGs. Other sensors such as millimetric radar may also find use. A very simple computer aiming system for use with such sensors suggests itself:-
The target is detected by the sensor and the information passed to a calculator sized computer which makes corrections for drop, lead and windage. The computer then generates an direction arrow on a LCD screen or HUD. It may also indicate how many degrees to swing the muzzle.
In this system the manual trigger arms the system the weapon is fired by the computer automatically when the muzzle is in the correct position. This system would be most effective for airborne targets, but may also have ground applications.
An interesting sighting system has been introduced for the grenade launcher for the FN F-2000 rifle. A rangefinder lases the target and an LED lights up when the weapon is raised to the correct angle for firing. A similar system could see broader applications, including for long range machine gun fire.
When ideas were being fielded for the OCSW, Ares suggested a 50 calibre weapon using telescoped rounds, each holding either a multiple flechette loading or a long rod penetrator.
The OCSW was to become a bigger brother to the OICW, but what if the Ares suggestion was used for a weapon of a similar size to a GPMG? I call this new weapon a "Hose".
Like a GPMG, the Hose would be used at squad and platoon level, and fired from either bipod or tripod. Used from a tripod, performance may equal and complement that of the OCSW. A Gatling version could be made for vehicle mounting.
I can imagine the weapon's rounds each resembling something like a 20 gauge shotshell, and the weapon being fed by a mixed belt of both kinds of ammo.
The long rod penetrator rounds will probably include a tracer/incendiary element and would have formidable capability against body armour and lightly armoured and soft-skinned vehicles.
If the flechette round is made along the lines of a shotgun shell I'm doubtful that the darts will stay in a tight enough pattern to give a useful effective range. It is possible that the flechettes may have to be carried in a "bus" round fitted with a range programmed fuse and a bursting charge. This would require electronics to rangefind and program rounds, much like those needed for the OICW and OCSW. Possibly the same device could be used for all these weapons.
Rick Randal on quietening MG belts:
Two ways that work fairly easily:
1. Dump the hardshell box for a soft sided case (preferrably zippered). Use a material that is somewhat flexible, but not flimsy -- about like an M60 spare barrel bag. The belts will "rustle", but will not clank back and forth. The soft sided cases have the advantage that if you are retaining the empty cases, you can scrunch them up easily enough.
2. Have the FACTORY insert semi-flexible shims fore and aft in the current boxes (the 200 round "drums") when loading ammo. Not a meterial like foam (there is a good chance of the bullet noses hanging up on foam), but about like a piece of corregated cardboard covered in 100mph tape. A little give, but a low friction coefficient. Not as quiet as the soft sided case, but better than the current "unmuffled" situation, and better than a piece of MRE cardboard (with or without the 100mph tape). There is still a chance of a partially empty "drum" having right-left or up-down movement of the belt and coming into noisy contact with the sides, floor, or roof of the box. But it's a solution with minimal impact -- just an added step in loading the belts into the drums, and a minimal material cost.
1) The US army did use small numbers of the French Chauchat machine gun a weapon troops found to be literally "worse than nothing". Many were simply thrown away. back
2) Using a 105gr bullet, the XM732 6x45mm round still has the potential to be a better rifle and light machine gun round than the 5.56mm. At the time there were no proposals to use the round in any other weapon so adoption of the XM732 would have been an unnecessary logistical complication. A more prudent course would have been to build a 5.56mm weapon that could be upgraded to the new round if necessary. back
3) The M1941 and M1944 Johnson machine guns were used by the US Rangers, USMC and "Devil's Brigade", and the Stoner 5.56mm machine gun was used in Vietnam by the Navy SEALs. There have been attempts to create squad automatics from the M14 and M16, but while many nations have made quite effective weapons by fitting heavier barrels to assault rifles (RPK, LSW-L86, Beretta AR70) American attempts have never been totally satisfactory. back
4) Possibly the fact that the M249 is used at fire team rather than squad level has prompted another (even more confusing) change in nomenclature. Possibly in homage to the Browning weapon the M249 is now called an "Automatic Rifle". One can only pity drill sergeants who have to explain that an M16 is not an automatic rifle, even though it is a rifle and automatic. back
5) Interestingly, by changing a few components this can be reconfigured as a 5.56mm LMG back
6)The Russian ZSU-23-4 anti-aircraft system uses liquid cooled cannon. back