Even with tanks and aircraft, the foot soldiers remain an essential element of modern armies, both because there are tasks they do best, and because even the richest nations can't afford to equip millions of soldiers with tanks.
This essay details the various classes of weapons carried and used by infantry soldiers, including the multiple classes of guns:
When World War 2 begun, most soldiers were equipped with bolt-action rifles. A 19th century technology, these rifles were powerful and very accurate weapons, effective to a long range of over half a mile, but since they required manual reloading after each shot, they were never suitable for combat situations which demanded a rapid rate of fire, and were therefore replaced during the war by newer weapons.
The only combat role where bolt-action rifles are the best even today, are sniper rifles, where their long effective range and high accuracy are the only things that count. These are bolt-action rifles which are adapted with magnifying telescopic sights, and often also with additional enhancements such as bipods, cushions, and higher standard production, all in order to maximize the sniper's ability to deliver the few selective shots that can sometimes affect the battlefield more than a hail of less accurate bullets.
Semi-Automatic Rifles were the natural development from the bolt-action rifle. By simply adding an automatic reloading mechanism, these guns provided the soldier with a significantly faster rate of fire, not just technically, but also because he could keep his aiming eye on the sights and on the target between shots, making continuous aiming and firing possible. These quickly became the basic personal weapons of World War 2 soldiers.
A German invention from the end of World War 1, these are the small and handy equivalents of machine guns, capable of a rapid rate of automatic fire, much faster than possible with a rifle, and they were also mechanically very simple and reliable, and also very cheap and easy to produce. Their smaller and lighter ammunition, similar to that of pistols, meant that a soldier could carry many more bullets than a rifleman. While they give each soldier a tremendous firepower, their main disadvantage is their significantly lower range and accuracy, even in single shot mode, which is the combined result of weaker ammunition, shorter distance between the front and rear sights, and simpler and less precise production. These features made sub-machine guns the weapon of choice for short-range combat, elite storm troops, tank crews, and it was also very attractive to armies which needed to urgently mass-produce weapons in the early stage of the war. Most sub machine guns of World War 2 were similar to each other, as they all had the same simple and successful mechanism of the original German MP18 sub machine gun, and wartime improvements were focused on making them even simpler to produce.
These all-purpose guns were developed and used by the German army in the 2nd half of World War 2 as a result of studies which showed that the ordinary rifle's long range is much longer than needed, since the soldiers almost always fired at enemies closer than half of its effective range. The assault rifle is a balanced compromise between the rifle and the sub-machine gun, having sufficient range and accuracy to be used as a rifle, combined with the rapid-rate automatic firepower of the sub machine gun. Thanks to these combined advantages, assault rifles such as the American M-16 and the Russian AK-47 are the basic weapon of the modern soldier.
Pistols are generally not suitable for military fighting. With their very short effective range and little ammunition, they are carried in combat by soldiers who are not expected to use them as their main fighting weapon, such as airmen, senior officers, non-combatant soldiers, and other military roles which for practical reasons, or even traditional reasons, are not carrying a sub-machine gun or a rifle.
The machine gun, as its name suggests, mechanized killing in World War 1 with its ability to fire a continuous hail of bullets at the enemy troops, with a very rapid rate of fire and a long range, making it an important element of the military unit's firepower, in addition to the personal weapons. The natural development in World War 2 was the light machine gun, which was light enough to be carried by a single soldier, with another soldier or two carrying additional ammunition, a quick change spare barrel, a tripod, or other parts. These high firepower weapons remain in service today, both carried and mounted.
Blitzkrieg, the devastating German tactic of rapid advancement of large formations of tanks, was so successful in the first years of World War 2 because anti-tank weapons were not very efficient and were not available in large numbers.
These were mostly towed direct fire artillery guns.
Infantry-carried anti-tank weapons, such as extremely powerful rifles with special armor-piercing bullets, were initially rare, and later became obsolete.
Infantry anti-tank weapons began to mature only with the deployment, during the war, of hollow charge warheads, a simple technology in which an explosive device is shaped with a circular V-shaped cavity, resulting in a directional explosion that concentrates most of its energy in one direction, creating a momentary stream of hot gas that hits the target with such tremendous pressure and heat that it pierces through steel and fills the hit tank with a spray of molten steel, killing the crew and setting the tank on fire.
The greatest advantage of hollow-charge weapons from the infantry point of view, is that unlike the projectiles fired from guns, which can penetrate armor because of their high velocity, like an arrow does, the hollow charge does it only by its unique explosive effect, regardless of its speed. This enabled the development of simple and effective lightweight anti-tank weapons, which could be easily operated by a single soldier, and it meant that for the first time the infantry had a truly mobile anti-tank weapon they could carry.
These weapons usually had a small rocket that launched the weapon from the firing soldier to the target tank. The only disadvantage of these lightweight rocket weapons was their short effective range, due to low accuracy. Only after World War 2 this type of weapon matured with the modern anti-tank guided missile, a small and highly effective anti-tank weapon, second only to the mighty guns of other tanks.
Artillery has been an important support weapon since ancient times. The explosive hand grenade is the first weapon which provided soldiers with personal artillery they could carry in their pockets, which was as easy to use as throwing a stone, and as lethal as an artillery shell. In the battle of Stalingrad, some Russian units took only grenades and knives to stealthy night raids, not guns. Thanks to their simplicity and low price, grenades are still used by all armies.
Like machine guns, light mortars are a unit weapon, its self-carried quick-response artillery, with maximum ranges from several hundred meters to several kilometers, depending on size. Unlike remote heavy artillery support, which was requested and directed by radio instructions, light mortar operators often saw their target and could therefore precisely aim at its direction and make quick aiming corrections, making it more effective.
Another World War 1 German invention, this powerful but very short ranged weapon provided a simple way to kill the enemy by fire, especially a fortified or dug in enemy which could not be effectively hit by gunfire or grenades. It operated simply by spraying a stream of ignited flammable liquid at the target, and operation was dangerous because it was to a very short range (about 30 meters) and immediately revealed the operator's position to counter fire from remaining enemy forces. This problem was partly solved by the development of flamethrower tanks, which protected the operators, and also carried much bigger and more powerful flamethrowers.