Early light weapons systems generally included only guns. In the daytime, it is easier to aim because of the good light, but at night, it is difficult to find the target. Sights began to appear during World War I, but they were not distributed in large quantities until after World War II, and only some snipers were qualified to use them. In the 1960s, the distribution of sights was expanded, which enabled operators to shoot long-range targets more accurately, but the firing rate was also greatly affected. These sights are extremely accurate, which improves the aiming accuracy, but also greatly prolongs the aiming time. Therefore, light weapons equipped with sights were mainly used by professional soldiers such as snipers at that time, and were not distributed to ordinary soldiers as standard devices. In addition, this kind of sight does not solve the aiming problem in the night battle.
In 1980s, with the invention of adhesive tape and the change of tactical demand, the United States and other countries began to issue tactical flashlights to soldiers as emergency lighting means. Tactical flashlight brings convenience to the night battle, but it also makes the operator easy to expose, because the dazzling white light emitted by the flashlight is too obvious, and the flashlight originally distributed is awkward to use and troublesome to switch. But at this time, after all, soldiers don't need a flashlight in one hand and a gun in the other, so it is more convenient to move.
With the development of time, the zero parallax red dot sight in M68CCO began to distribute a large number of troops in the 1990s. This sight device enables shooters to aim at targets at any distance and improve the shooting speed. Then, AN/PEQ-2 infrared laser aiming/aiming device appeared almost at the same time, which basically solved the aiming problem in the night battle. With this device, the shooter only needs to project the red dot in the sight onto the target, then pull the trigger, and the rest is done by the kinetic energy of the bullet. The emergence of these devices raises the question, where should they be placed in light weapons? When fixing them with adhesive tape, why not cover some important parts, such as the shell opening?
The guide rail has various accessories.
At this time, the guide rail system came into being. Picatinny accessory guide rail system (MIL-STD 19 13) invented by Picatinny Arms Company of the United States enables shooters to assemble weapons as required to meet the requirements of different environmental conditions. At first, the guide rail system was designed for large caliber rifles, so that it could be equipped with optical precision aiming devices. However, people soon found that besides the sight, many accessories can be installed on the guide rail system, such as laser pen/sight, flashlight, tripod, bayonet fixture, spare weapon sight and customized handle for melee.
Some western companies are now producing complete sets of guide rails for military weapons, such as GG &；; Company G has introduced a complete set of guide rail packages of M 16/M4 in the market, including five guide rails to replace the handles and hand guards of M 16/M4. Knight Enterprise designed a floating barrel weapon system (RASII). In this system, the guide rail is hung on the barrel, so the barrel is less disturbed when shooting, which can improve the accuracy. There are also some companies that mainly develop accessories that can be installed on the guide rail, such as various sights, night vision devices and laser pens.