A64 Jackhammer GPMG

== Overview ==
The A64 Jackhammer GPMG is the tried and true workhorse of the Iron Coalition, striking fear into those enemies who are unfortunate enough to hear its warcry. It is a 10mm x 56mm fully automatic machinegun with a standard 200 round capacity, with options for 300 and 400 round magazines. The design was developed by Beman Collerus of Mckinney Ordinance Factory alongside the A15 Hammerhead in Y4138 as part of Project Austenite. It fires from an open bolt, and employs a barrel made of the novel compound Nitrexite, an inherently endothermic steel composite. 
The Jackhammer is at the heart of each squad, providing the bulk of suppressive fire. Once a Jackhammer squad has deployed its bipods, it will be extremely difficult if not impossible to dislodge them from their position. The A64 has been used against the Pax-Viribus Theocracy to deadly effect, particularly in the hot and arid conditions beyond Forward Operating Base CD42-V and the Gulf Of Kemet.
=== History ===
Even before the Perennial Wars, the Iron Horde was already looking forward to replacing the heavy machine guns such as the A14 Centurion which proved to be such a success in the bitter war with rebel group Wian's Wrath. The older A35 Jakkal was one of the first developments toward a goal of producing a weapon that could perform multiple roles, rather than just one. The A35 was the result of reengineering the Dondergeweer Toestel 01 (DGw T1) to fit the new requirement specifications.
This eventually led to the "Multi-Purpose Mobile Machinegun", introducing an entirely new concept in automatic firepower. By changing its mount, sights and feed mechanism, the operator could radically transform an MPMG for several purposes.
The A35 Jakkal is regarded as the original modern MPMG, or general-purpose machine gun. It was designed to work with the common IC 10mm x 56mm full-power rifle round. It was designed with the intention of providing infantry cover for light and medium machine guns on the move, low level anti-aircraft protection, and even sniping capability. The A35, which had a heat-resistant barrel and could fire for much longer periods of time than other portable squad-level weapons like the Velocitan Army's Monsoon Model 4 or the PVT Deluge Machine Gun (DMG-3), which were fed by magazines, as well as being much lighter and more portable than crew-served weapons like the A14 Centurion, VG-12 Dover or Repenter machine guns. The A35 was also quite versatile; not only was it able to be fed from belted ammunition or a box magazine, it could also be fired from a bipod, tripod or various pintle mounts for armored vehicles. Switching between a bipod and a tripod required no special tools, as the mounting latch was spring-loaded. It was also used throughout interwar conflicts as secondary armament on Bellows MBTs and other vehicles .
The A35 was not without its drawbacks however. With high production costs, time intensive milling of parts and a complicated manual of arms, the Iron Ordinance Department started looking for ways to simplify and streamline the design and concept. In early Y4136 a solicitation was sent out to choice entities, one of which was Mckinney Ordinance Factory. Beman Collerus, one of the leading design engineers with MOF, knew nothing about machine guns when he was given the task of being involved with the project, although he specialized in the technology of mass production. Collerus would embed himself for a month with an IC machine gunner detachment to learn about the tactics and weapons employed, also seeking input from soldiers.
After many iterations and design improvements the final design was accepted by the IOD in T2 Y4138 M27 and designated the A42 Jackhammer. The A42 was first deployed in Y4140 by the 1st Iron Expeditionary Force (IEF) along the Gulf Of Kemet as a precursor to the 1st Battle of Bulwark, and introduced by mid-Y4143 on all fronts. Production during the war stands at over 400,000 units, and use/improvement of the weapon system continues to this day.
=== Operation ===
The current iteration of the A64 utilizes as much modern technology as is practical, making it a deadly force on the battlefield. Of primary concern with main machineguns is their tendency to overheat during battle. To address this the A64 utilizes an experimental barrel made of a Nitrexite-Steel endothermic composite . This ionized material reacts with the ambient air producing an endothermic reaction that can cool the barrel to sub-zero temperatures. Upon firing, the barrel is heated back up, reversing the reaction and allowing it to begin again. Barrels with this property must be used by trained personnel only however, due to the fragile state of the barrel if allowed to fully react and cool. If dropped or banged in this state, the multi-million dollar barrel could shatter irreparably.
While this property allows for increased time operating the weapon, crews can exhaust their ammunition supplies quickly. Carrying more ammunition is a potential solution, but an auxiliary device such as a Munitions Load Escort (M.U.L.E.) must be used, which is not ideal in certain engagement situations. Hence the A64's receiver can be swapped out to another one which can receive caseless ammunition, thus saving a tremendous amount of weight.