A barrel is a part of a gun. It is a long metal tube that the bullet or projectile goes through after it is fired. Guns can have many different sizes of barrels. Usually, longer barrels make it easier for the bullet to hit the target more often. Barrels usually have spiral grooves on the inside called rifling. Barrels with grooves spin the projectile around faster as it exits the gun. This makes the projectile more stable in flight and more accurate.
Shell (projectile)
A shell is a type of projectile used in weapons. It is filled with explosive or other things such as an incendiary device. It is similar to a bomb but is made to be shot out of a gun. Shells are usually large caliber projectiles fired by artillery, armored vehicles (including tanks), and warships. A fuze detonates the explosive or releases whatever else the shell may be carrying.
Anti-tank guns fire thick shells without much explosive inside. Shells usually have the shape of a cylinder but taper towards the front end to form a point. However, special shells may use other shapes.
Ion thruster
An ion thruster is a kind of spacecraft engine. It works by using static electricity or magnetism to push ions (electrically charged atoms) out the back of the spacecraft. It takes a very long time to speed up, but its fuel lasts much longer than a rocket engine. It has to be carried into outer space by a regular rocket, because the ions don't push hard enough for it to escape the Earth's gravity, but after it gets to outer space it can travel a very long way. An ion thruster needs electricity to run, so the spacecraft has to also carry solar panels or a nuclear reactor.
In 2011 the NASA space probe called Dawn used an ion thruster to get to the asteroid Vesta. In 2015 the thruster brought it to the dwarf planet Ceres.
Pistol
A pistol is a handgun. The word may be used broadly to mean any handgun, or narrowly to mean only a magazine pistol, as distinct from a revolver.
In a magazine pistol, the cartridges are in a magazine, which is a metal or plastic box. The magazine is usually inside the handle of the pistol. When the pistol is fired, the empty cartridge pops out, and the next one comes up into position. The magazine is spring-loaded so it pushes the next bullet into place as the empty cartridge is ejected. For that reason pistols are sometimes called "semi-automatic". When the magazine runs out of cartridges, it can be reloaded by inserting more cartridges.
The term has long been variously used. For example, in the American Old West revolvers were used but were then (and even today by some) called pistols. The word "pistol" entered English before 1600, from the French. At that time it usually meant a single-shot handgun.
One of the most important rules of gun safety is to keep guns out of the hands of children. Guns should be locked up and kept away from children and others who do not appreciate how deadly they are. Pistols like all guns should always be handled carefully. Always keep the gun pointed in a safe direction. A shooter should keep their fingers away from the trigger until the moment they intend to shoot. Always respect guns as a tool that can cause harm if used incorrectly. Always assume a gun is loaded until you are certain it is not.
A bullet is not the only part of a gun that can cause injury. Hearing protection will protect the eardrums of the shooter and those nearby. These can be inexpensive foam earplugs or more costly hearing protectors that have a Noise Reduction Rating or NRR. The higher the NRR number the better. Eye protection should be worn at all times while shooting or observing other shooters. Their impact-resistant lenses protect against bullet fragments, stray bits of gunpowder, and other debris.
The advantage of pistols over revolvers lies in the somewhat faster reloading of magazines that carry more bullets that a revolver's five or six rounds. This is why most police and military organizations use pistols. Also, pistols are often thinner and can be worn concealed better than revolvers. Pistols are generally regarded as being safer than revolvers. A revolver can fire accidentally if dropped. A pistol rarely fires if dropped. A common feature of pistols is a lever called a safety. The safety prevents the pistol from firing even if the trigger is pulled. To fire a pistol, first remove (turn to the off position) the safety.
Pistols have a few disadvantages when compared to revolvers. They are more complicated and have more moving parts. A pistol may use heavier springs that younger and elderly shooters may find difficult to use.
Modern pistols usually only fire one shot every time you pull the trigger. Some special pistols, called machine pistols, can fire more than one shot at a time. Some famous pistols are the Colt M1911 and the Beretta 92.
Pistols were not often used in the western United States during the 1800s. They used revolvers. The first successful pistol being used then was the Borchardt C-93. It was designed in 1893, and became available in 1894.
Submachine gun
A submachine gun is a type of gun that shoots many bullets, usually pistol bullets, when one holds down the trigger. A submachine gun is smaller than a machine gun and can easily be carried by one person. They are often used where people need to defend themselves in small areas, or people need to fire many bullets quickly. The first submachine guns were invented in the early 1900s. They are often used by the police and counter-terrorism units .
In the early 20th century, experiments were made by converting pistols from semi to fully automatic firearms. Stocked (with handle) automatic weapons firing pistol rounds were developed around the same time during World War I, by Italy, Germany, and the United States. The first dedicated designs were developed in the latter stages of World War I both as improvements on earlier stocked pistols, and to offer an advantage in trench warfare.
They were popularized in the 1920s and '30s as weapon of choice of American gangsters and police, in the form of the famous Thompson submachine gun, commonly referred to as the "Tommy Gun". Submachine guns rose to prominence as a frontline close-quarters combat weapon and commando firearm during World War II. They are now widely used by police SWAT, military commando, paramilitary, and counter-terror team members for a variety of situations.
Submachine guns are highly effective in close quarters; their lower-powered pistol cartridges make them generally more controllable in fully-automatic fire compared to assault rifles, while their small size and light weight grant maneuverability. However, pistol bullets often are stopped by body armor or cover, and are short-ranged compared to intermediate and rifle cartridges.
World War II developments were many and interesting. In Germany the development of machine carbines ("Maschinenkarabiner") was notable. From 1939 onwards the German Army analyzed combat conditions and developed new tactics and equipment requirements. The existing 7.92x57mm rifle cartridge was more powerful and long ranged than needed. Most combat took place at ranges less than 400 m (440 yards). A less powerful round (bullet) could be used. This meant a soldier could carry more ammunition, the weapon could be shorter, lighter and with less recoil. The gun could be an automatic.
Achieving this took time. Work in 1941 and 1942 led at last to a reliable weapon, the StG 44 (Sturmgewehr 44) "assault rifle 44". This was then produced in large numbers (over 600,000). It came too late to effect the Second World War, but was later adapted as the Soviet AK 47.
Elena V. Pitjeva