The Winchester Model E, U.S. Military designation M18 was an early laser rifle from the mid-21st century. Developed by the brand new "Energy Weapons" branch of the Winchester Arms Company in the early 2000s, the first M18s were bought by the United States Department of Defence in 2053 amidst the start of the Resource Wars. It was only deployed in limited numbers, and in its initial form was plagued with reliability issues, but its potential would pave the way for the adoption of the AER9 laser rifle toward the end of the Wars.
The M18 was the first real attempt at a general-production energy weapon. Development dated back to the late 1990s when the Department of Defence began declassifying documents -- among them, analysis and full specifications of the EG42 radiation rifle. Winchester Arms Company, which at the time was in rough straits financially, singled out the EG42 documents and had a team of gunsmiths study them, attempting to both backwards engineer the rifle -- which itself was actually quite a simple device, more or less a glorified housing for the power source -- and make use of more modern developments to create a viable energy weapon, the intention being to acquire a government contract.
A billionaire bought Winchester at the turn of the millennium, eradicating its financial woes, and the project continued. The team had, however, hit a wall -- not only was the weapon they had backwards-engineered extremely heavy and bulky (being made almost solely from lead and titanium), but it proved extremely difficult to direct outside of "point and pray", and its power source was lethal. Other types of 'projectile' were experimented with: plasma, though a good cutting agent at short range, was unviable for a rifle at the time. Most lasers at the time, though capable of being projected over a long range at various strengths, were too diffuse, too weak, or too energy-sapping to work as a rifle.
The development of the microfusion cell changed that.
A self-contained fusion reactor, no larger than a car battery (with weaker models being no larger than the size of a soda can), offered seemingly endless opportunities. It essentially ended the American fuel crisis, which had been picking up speed as the Resource Wars approached.
Lasers quickly became the obvious choice for effective energy weapons. Unlike radiation, they were visually easy to adjust the aimpoint, and furthermore were extremely precise. Unlike plasma, the laser offered range. Winchester's team fine-tuned a mirror array and focus, attempting to get the laser as concentrated and powerful as possible, making use of the microfusion cell's full potential.
The result was a one-shot weapon that was capable of burning through flesh and bone, which was assembled into a rifle-type housing and dubbed the Model E.
After years of service in the Resource Wars, the Model E would later be refined -- a limiter would be added to the weapon which would be more efficient with the power supply, offering five one-second bursts instead of one burst per cell. Additionally, the frame would be reinforced and the internal parts made more shock-resistant in time. However, despite these improvements, the M18 would eventually be rejected by the Department of Defence overall in favor of the AER rifle which had been developed in the intervening time between the M18's limited adoption and the approach of the Great War.
The M18 saw its first deployments during the Resource Wars, under the designation M18A1, where it was used in limited numbers by American supply corps units who were deployed to support European forces. Though largely behind friendly lines, protected from outright fighting, the M18's stints in the dry, sandy conditions of the Middle East exposed a number of issues. Continued usage of a rifle more than one time within a short timespan would almost always break some of the critical parts -- the focusing mirrors especially were prone to warping, while the industrial glue that held the rifle together could easily melt away and cause pieces to fall off. The inefficient nature of the weapon meant that only one round could be fired per microfusion cell -- before the cells themselves were improved and miniaturized, this meant that a single soldier could only carry four or five rounds (which each were about the size of a car battery), and reloading was a slow procedure. Over time, not only were the cells improved to the point that they were no larger than a soda can (with the same level of energy output per cell), but the rifle itself was made more efficient, with less energy being lost as heat, which greatly improved the carrying capacity of the average soldier.
The Model E 950, under the designation M18A2, saw limited action amongst the United States Marine Corps during the Sino-American War. Lighter, more accurate, and more efficient, it was significantly more impressive than its original iteration had been over a decade beforehand. Even under the varying conditions of the Chinese mainland, improved materials and sealant made it more reliable, and the improved transfer of energy (which eliminated much of the melting issues the older variant suffered from) meant that the A2 required less maintenance.
The M18, in either form, was never released to the general public. Most units were overseas at the time of the War, or were otherwise locked away in military armories or Winchester production facilities -- all of which were high-profile targets during the War. And even of those that did survive and somehow were recovered, the M18A1 suffered from constant breakages in the post-Great War world, and the M18A2 was inferior in most ways to the more common AER9, meaning that the few M18A2s that did survive were typically broken down and used for spare parts for the AER series of rifles.
By the mid-2200s, the M18 was essentially nowhere to be found.