This section is intended to give a brief overview of the general issue military rifles, used by various nations during the XX century. This section is further divided into two subsections – bolt action rifles and semi-automatic rifles.
Bolt action rifle is a weapon, which requires a manual operation to reload a weapon prior to each shot. Term "bolt action" comes from the "bolt" – a part of the weapon that is used to feed cartridges into the chamber and to lock the barrel upon the fire. This part also is more generally known as "breech block", but the term "bolt" is usually referred to the longitudinally movable breech block. So, to fire each shot from bolt action rifle, one must manually unlock the bolt, open it to extract and eject spent case, close the bolt, feeding a fresh round into the chamber simultaneously, and then lock the bolt. When trigger is pulled, rifle goes off and another set of manipulations described above is required prior to the next shot can be fired. Bolt action rifles could be further divided in numerous sub-categories, such as single-shot or magazine-fed rifles, rotating bolt or straight pull bolt action rifles etc, but this will not be discussed here, at least for now.
First bolt action rifles appeared somewhere in the mid-XIX century, and first magazine fed bolt actions were adopted by the Swiss army in the 1870s in the form of the Vetterly-Vitaly rifle. Since then and until the end of the World War 2, bolt action rifles and carbines were the main individual infantry long arms.
It should be noted also, that the term "carbine" refers to shortened and lightened rifle, does not matter if it is bolt action or semi-auto.
Semi-automatic rifles differ from the manual repeaters in fact that semi-automatics used some amount of the energy, generated by the each shot fired, to commence the reloading cycle (extract and eject the spent case, feed a live round and lock the action, cock the hammer or striker). Due to this, semi-automatic rifles are often referred as a self-loading rifles, too. So, as long as a cartridge supply to the action remains uninterrupted (magazine is not empty), gun will fire each time the trigger is pressed, without any other manual operations. However, when gun is loaded for the first shot, it usually requires at first manual loading cycle to be commenced. The key difference between automatic and assault rifles and semi-automatic rifles is that the semi-automatic rifle will fire exactly one shot per each trigger pull, while automatic (assault) rifle will continue to fire continuously as long as the trigger is pulled and cartridge supply to action is not interrupted. First semi-automatic rifles appeared at the end of the XIX century, but it was not until the 1930s when semi-automatics began to proliferate into the military service. The World Wars 1 and 2 gave a birth to the numerous design that were designed and issued to troops in 1930s – 1950s, but fast proliferation of the selective fire assault rifles made the day for semi-automatics in general military service.
Many bolt action and semi-automatic rifles are still in limited military service in the form of Sniper weapons, but this particular category is discussed elsewhere on this site. This particular section will describe mostly general issue infantry weapons.