MODEL 50 | HEAVY MACHINE GUN
The Model 50 Heavy Machine Gun was developed towards the end of the twentieth century for use primarily by the Kings Highland Rangers, to replace their then aging M2HB Heavy Machine guns that had served them well for almost a century. Though there we no complaints about the formers reliability or accuracy, there was a growing doubt that they could continue to perform against the continuing march of AFV armor improvements. At the same time, concerns about ammunition volume began to take center stage as larger and larger rounds were considered. It took almost eleven years of research and development to develop a workable prototype, and another three of military trials before it received the Kings Seal and accepted as a Official Pattern weapon before being was issued to Amastoli troops in 2007.
Two years of service in the many separate branches of the Amastoli military have made for a large number of minor changes reshape the Model 50 Heavy Machine Gun into the product it is today. Despite its long development process, it would seem however that the Model 50 is not quite finished with its evolution. Confident in their product with domestic contracts already secured, Argus has recently begun offering export contracts for its premiere Heavy Machine Gun for the International market. Argus however knows that few countries would be willing to convert to a new caliber if they were not familiar with the new rounds ballistics, so Argus developed the Model 50 with a new modular bolt and universal barrel lock to allow for a wide variety of chambering options befitting international export. This modular approach allows the Model 50 the flexibility to adapt to a foreign nations needs without sacrificing reliability or performance.
The Model 50 HMG is used in New Hayesalian service in a number of roles, including as a support weapon, coaxial turret, and ship-based crew served weapon.
The Model 50 is a short stroke, gas-operated, tilting-bolt Heavy Machine Gun, designed for use primarily as a vehicle-mounted weapon either internally or externally. Despite this it has also found its way onto the battlefield in the care of Amastoli Heavy Weapons and Air Defense teams where it has distinguished itself due to its high reliability and superior firepower. The action is operated by a pair of self-regulating short stroke gas pistons located below and to either side of the barrel. These gas pistons are of the self cleaning type, and siphon gas from a tap sixteen inches forward of the chamber providing more than ample pressure to operate the weapons heavy operating rods even while muddy or fouled. After firing gas is tapped from below and to either side of the barrel, which forces the dual operating rods rearwards. The two operating rods strike a projection on either side of the bolt carrier, which ride in cams cut into the receiver walls. The rearward action of the pistons, acts on the bolt and forces it up and out of its locking recess in the sides of the receiver. Once unlocked the bolt is free to continue rearward completing the extraction of the spent round.
Meanwhile a short metal projection at the rear of the bolt carrier is topped with a hardened metal post, which engages a cam grove in the feed pawl attached to the feed cover. The rearward movement of the post acts on the feed pawls cam, moving the ammunition belt forward a whole step. After the bolt has reached its maximum rearward movement, the recoil spring overcomes the bolts inertia and drives it forward again resetting the feed pawl for the next round. The bolt, now on its forward travel then strips out a fresh round from the belt and chambers it. When the bolt fully engages the barrel extension the bolt carrier is forced down into the locking recesses locking the bolt to the barrel extension and allowing the firing pin to strike the new rounds primer. The chamber is fluted to prevent stuck cases during extended firing, and decrease the likelihood of a cook-off by decreasing surface area contact with the rounds, increasing reliability in the field.
The barrel of the Model 50 series is a heavy hammer forged barrel designed for maximum heat dispersion, low harmonics, and high accuracy without an exceptionally large dispersion area. The Heavy barrel of both the Quick-change and Fixed barrel versions are air cooled and developed to provide maximum heat dissipation within their given thickness, so as to support sustained fire against point or area targets. The use of polygonal rifling allows for maximum barrel thickness at all points, and does not introduce fatigue or material loss along the length of the barrel. The polygonal rifling due to its lack of hard cutting grooves collects less fouling in both the form of unburnt powder or jacket material. This allows for extended performance and accuracy without fear of degradation of weapon accuracy or secondary corrosion concerns after several hundred rounds of fire.
The core of the Model 50 is composed of a U-shaped machined steel receiver that holds the majority of the weapons operating components, and reinforces the locking recess, barrel extension, and sidewalls of the receiver for added strength and reliability in action. This keeps weight down, yet adds exceptional strength to the areas of repeated wear or impact. AN L shaped Steel bracket supports the dual full-length guide rods for the bolt and recoil springs, and are designed to interlock with the U-shaped receiver by means of a rear locking pin. This combined metal to metal interface means that despite the reduced receiver weight, no strength or reliability is lost. This L-bracket also forces the blast force of any potential catastrophic malfunction up and away from the user, while the lighter polymer side walls reduce potential injuries due to spalling dramatically. Combined this increases operator safety in the unlikely event of a damaged high pressure cartridge.
Working components of the Model 50 are Melonite and QPQ Salt Bathed Nitrocarburized (SNC) to produce a naturally scratch resistant, dry lubricated surface that provides three to four times less friction than hard chromed surfaces allowing the weapon to operate without additional lubrication for long stretches of time without undue damage to its working parts. In keeping with the general design philosophy of ARGUS, all major working components are investment cast, and then machined to specification in steel. This fine detail control and use of MIM and CAD/CAM construction however does not mean that the weapon is designed to fit tightly together like some would expect a precision rifle to be. Instead the tight tolerances and overcast pieces allow for reliability while still making each piece exceptionally strong, with plenty of operational space within the receiver to allow it to continue operating whether dirty, fouled, or under maintained.
The outer cover and sidewalls of the Model 50 are made of highly impact-resistant Long Fiber Reinforced Polymer (35% glass), A high temperature, high strength polymer that though it does not take the firing stress of the action directly (the milled steel receiver does) reduces the weight of the weapon by replacing the heavy stamped steel exterior used on most contemporary heavy machine guns. The polymers increased Specific Tensile Strength (KSI) over Steel (ASTM A131) and Aluminum (6061-T4), and reduced wear due to vibratory stress increases the service life of the weapon without sacrificing reliability in the field. All major parts are solid molded to fit, and provides a matte non-reflective solid color that does not wear off with age or use like painted steel would.
Beyond its modular bolt and design allowing for several different chambering options, the Model 50 has two specific role based variants. Though operating in the same manner the main differences between the two models lay with the means of control and the sights of the weapon. The Model 50E; which has spade grips, and a quick change barrel, and was designed to be pintle or tripod mounted. The Model 50T which has a heavy barrel, and a solenoid trigger is designed specifically for Coaxial and Remote Weapon System mounting. Though both weapons are identical ballisitically they are not interchangeable due to their control scheme. In order to better clarify the two variants differences please see the descriptions below.
The external version of the Model 50 Heavy Machine Gun (or Model 50E) is designed for use by infantry or as attached to the cupola on many Armored Fighting Vehicles or Support Vehicles. The iron sights on the weapon are folding sights, based on the popular Stonewall sight system and are fixed to the receiver forward of the feed cover. They retain their zero even while folded allowing for them to be brought into action quickly and easily by pressing forward on the action bar, which releases both spring loaded sights at once (though they must each be lowered manually). Sights are of hooded post front, and aperture rear, with rear adjustment for range and windage. Contrasting orange/green tritium sight inserts are standard on all Amastoli versions, but are optional on export models; with white enamel markings being standard. In addition to the traditional folding iron sights the Model 50E features an M1913 specification rail interface system offset slightly to the right and to the rear of the feed plate to allow for uninterrupted use of the iron sights should the mounted optics malfunction or break.
A non-reciprocating charging handle is attached to left and right side of the weapon via the action-bar extension at the base of the receiver. The polymer charging handle is capable of folding against the receiver to reduce its profile during transport. dual firing grips on the External version of the Model 50 are made of glass reinforced polymer, with rubber insets for operator comfort and improved grip. The grip themselves are shock isolated by means of a silicone buffer between the grip and the securing rod. This reduces transferred vibrations to the shooters hands decreasing operator fatigue, and increasing accuracy during extended firing sessions. The weapon is operated by a pair of joy-stick-style triggers, one on each grip is used to fire the weapon. On firing, both triggers to be squeezed for the first shot, but automatic fire can be sustained with only one trigger depressed. This is done to Improve weapon safety, without over complicating weapon ready procedures, and reducing shooter fatigue.
The barrel of the Model 50E is capable of being changed in the field via a reinforced bayonet lug that locks into the barrel extension. Removing the need to worry about head spacing when replacing the barrel in the field. The locking mechanism is controlled by rotating the barrel-carrying handle to the right side of the receiver to lock it down or rotated upwards to unlock it. The gas port is fixed to the barrel and once the barrel is unlocked, slides forward off of the gas tube assembly with it. The barrel-changing handle found on the External model of the Model 50, is also used for carrying spare barrels. The handle, like the Spade grips are glass reinforced polymer pinned to a steel handle bar. Forward of the barrel handle is a polymer barrel shroud of the same material, designed to give the assistant a second place with which to grasp and steady the barrel while changing removing it, reducing the necessity for special gloves or additional equipment while changing the barrel of the weapon in the field.
The internal version of the Model 50 Heavy Machine Gun (or Model 50T) is designed for use in Armored Fighting Vehicles or in Remote Weapons Stations (RWS) where it will not be operated directly by human hands. As such the weapon is fired by means of an electrical solenoid operating a mechanical sear. The primary noticeable difference between the Internal and External version is the much heavier barrel of the Internal version, which is designed for sustained fire fed from a larger ammunition supply than the external version. This barrel is not designed for quick change like the External version is, but can be changed in the same way through with the use of a standard twenty-two millimeter open-ended wrench instead of an integral handle. Because the weapon fires from a closed bolt in all its forms, gas exhaust bleeding into the internal space of a turret is highly unlikely, and the first round hit probability of the weapon supported within a vehicle is superb. The weapon also lacks the wide cocking handle of the external version being operated while inside a vehicle by a vinyl coated braided steel cable attached to a pull handle made of the same sturdy GFRP polymer as the rest of the weapons furniture. Feed and ejection remain the same, though a special attachment point at the bottom of the receiver for the attachment of a powered or un-powered (bag) collection of spent cases. Though a convenient feature when used inside a vehicle it is entirely optional.
Because of its high tech construction and design the Model 50 is nearly impervious to corrosion and, its range makes an excellent personal defense weapons for ships and vehicles both large and small. Its hard hitting capabilities and long range accuracy easily place it above similar smaller weapon systems. Its high rate of fire, with high ammunition storage capabilities allow it to compete even with heavier weapon systems in terms of firepower and destructive potential at range. Its lightweight outer components, combined with its low center of gravity give it excellent stability on a tripod with little breach kick up. Firing from a closed bolt its first round hit probability is excellent, a capability that is becoming increasingly important in the use of heavy machine guns in the field, both as mounted in vehicles or on a tripod. With is combination of low weight, high accuracy and advanced components it is a boon in the hands of infantry anywhere, able to suppress enemy units and light vehicles from over a kilometer away. When combined with the stability and armor of a vehicle the Model 50 is capable of providing sustained firepower over long distance and against hardened targets on the ground, sea, or air as may be required by its operator. With its profile slimmed down for use internally it takes up less room than many of its contemporaries while providing superior or equal capabilities for the same space. Lightweight, Accurate, Heavy Hitting, and able to operate independently of major logistics; the Model 50 is an excellent example of combat flexibility and lethality in the modern age.