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 Posted: Sat Jan 12, 2013 6:34 pm
Basic Weapons TrainingMost weapons used by the military have a semi-automatic, fully automatic, or burst function action. Semi-auto is a self loading weapon; one round fired per trigger pull, but the weapon automatically reloads. Fully automatic fires multiple rounds per trigger pull, until the magazine runs out, while burst fire will fire a set round per trigger pull, often 2-3. The magazine holds the bullets; this can range from 10-30, for medium capacity magazines, all the way to 100 for higher capacity magazines. Drum magazines often times hold more rounds, although they have questionable reliability. Most modern firearms utilize a detachable box magazine; this can also be referred to as a clip. Even in semi-automatic fire, a weapon needs to be manually loaded first. Since the weapon uses the backwards recoil of the previous round to load in the next round and cycle the weapon, a weapon must first be loaded manually before it can fire, and before it can be self loading for each round after that. After it has been manually loaded, once, it will be self loading (unless a bolt action or single shot weapon), unless the weapon jams, or fails to operate correctly. To clear a jam, generally you merely go through the same motion as manual reloading, deal with the charging handle or use the forward assist (present on some guns, like the M16). A barrel is what captures the gases of the gunpowder and gives rifling to the bullet. The longer the barrel, the more gases that can be captured, and the more powerful a weapon generally is. Gunpowder is actually not what is considered "gunpowder", but usually a mix between stabilized and gel like nitroglycerine and nitrocellulose; this mixture is generally called " smokeless powder". These materials don't explode, but burn, and deflagerate, building up pressure. When the pressure is built up, it expands in the direction of least resistance, which propels the bullet down the end of the barrel, the barrel of which captures these expanding gases, and accelerates the bullet. Because it acts so quickly, it can appear like an explosion. It is the expansion of the gases that predominately propels the bullet, rather than a shockwave, however. The stock of the weapon is simply a shoulder rest. Sometimes weapons have folding stocks, other times they have a very small stock. Bull-pup weapons have no stock, and generally are 8-10 inches shorter from traditionally layed out weapons. While they may have other complications of their own, they typically provide the best barrel to over-all length ratio. The shorter the weapon, the easier it is to aim at the target, bring the barrel on to target, and maneuver in close quarters. 24 inches is about what's necessary to clear most hallways, doors, and human sized openings. The P90 for instance is 20 inches long; at these sizes, the weapons do not need to be "ducked" to move around corners, which makes them significantly better at being moved through tight quarters and acquiring targets. Pistol rounds are generally slower and heavier than rifle rounds. A 9mm parabellum (stand military pistol round) for instance is 7.5 grams, at around 400 meter per second, as compared to an M16 round at 4 grams and 940 m/s. These differences make rifle rounds typically have longer ranges and higher energies, but sometimes have less stopping power. The recoil of rifles are generally higher, although this is not always the case with considerably more powerful pistol (or weaker rifle) rounds. Rifle rounds require longer barrels than pistol rounds, and generally larger guns. A Beretta 92F is around 2.2 pounds, while an M16 is closer to 7.5 pounds (unloaded). Despite this, both the M16 and Beretta both use cartridges of about the same weight, or about 12.5 grams. Cartridges are the entire round; the bullet, the gunpowder, and the case that holds them all so they are easily loaded into the weapon. The bullet is obviously, the kinetic energy projectile designed to do damage, while the gunpowder is the explosive/deflagratory material designed to propel the bullet down the barrel. The casing usually holds the gun powder and part of the bullet, holding the entire cartridge together. The cartridge is generally ejected by the weapon. The bolt, which propels the firing pin, usually strikes the primer, which is a small explosive charge designed to set off the main charge, or gun powder. A weapon operates by using a "cocked" spring, to propel the firing pin, designed to strike a small part of the cartridge, and then set off the primer, setting off the rest of the gunpowder. The primer is usually relatively hard to set off, and must use a powerful spring and bolt, generally for safety and reliability reasons. If the round is not powerful enough, it will not cycle the weapon.
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Posted: Fri Apr 05, 2013 11:20 pm
General weaponsAssault rifles are generally relatively easy to operate. You pull back the bolt, first "cocking" the weapon, which puts pressure on the spring and is held into place. This also simultaneously loads in the first round, as the spring from the magazine pushes the round into the chamber, which is now revealed. When the trigger is pulled, the cartridge moves into the breech, usually locks with the bolt, and then the firing pin strikes the primer, igniting the rest of the gunpowder, capturing the expanding gases, and propelling the bullet down the end of the barrel. When the bolt is opened, the round then generally ejects by the nature of the hot gases expanding backwards and outwards. Then, once the weapon is loaded manually, after the first round, the rest of the rounds will be self loading due to the recoil of the first round. Since there is no recoil for the first round, it must be loaded in manually. The receiver is basically the working mechanism of the rifle; the lower receiver generally houses the trigger group, bolt, firing pin, spring, and other such devices for the working mechanism, while the upper receiver usually houses the barrel, the gas operation, the iron sights, and many more such things. Some weapons possess a forward assist and a charging handle. The forward assist helps to load the round into the chamber if the gases were not enough to help load the weapon and the charging handle to help load the firing pin or spring. Both of these are designed to assist the primary mechanism and give manual control over a potentially jammed or improperly loaded round. You generally want to hold on to such a weapon with it pressed against your shoulder and holding onto the grip. It is prudent to keep your eyes on the sights and have them aligned at all time; for military purposes, you also want to keep both eyes open instead of having one eye closed. Thus firing the weapon requires you to aim, and look down the sights. Belt FedMachine guns are generally belt fed. These weapons utilize an alternate method of loading compared to spring fed magazines; the recoil of the weapon moves a lever which then cycles in more rounds based on it's interaction with the belt. Since belt fed weapons do not require springs, they can often have open or near unlimited magazine sizes. These weapons are generally top fed, with the rounds going into the weapon and the feed tray going down. Once this is established, the first round is loaded in manually and then the weapon becomes self loading. Most machine guns don't have a semi-auto function, so they generally only tend to fire fully automatic. More information on how rifles work in general can be found here; belt fed weapons more or less use an extra feed claw to operate. PistolPistols work essentially the same way as rifles, except they are smaller. Most pistols use a recoil blowblack operated system, that involves moving the barrel and generally the entire slide; this means the barrel reciprocates in the weapon, with a moving barrel. A recoil operated system primarily relies on recoil to operate, instead of diverting gases back into the weapon. Pistols are generally harder to fire then a rifle, due to the lack of a stock and the reduced accuracy of the shorter barrel of weapon. The weapon must be firmly held and aimed without assistance from the shoulder, which being smaller compounds the issue of recoil. They are however, as a result, significantly smaller and easier to carry around. As a result of their small size, they generally use smaller or less powerful cartridges; optimized for close ranges, they are generally heavy bullets, but are fired at incredibly slow velocity. This increases it's power but usually decreases the over-all energy. Given it's small size and maneuverability it is well suited for close range, and therefore does not usually need long range capabilities. Manually Operated WeaponsManually operated weapons require some manual assistance, that is operation by hand, to function. They must have a round loaded into the weapon after every shot in order to be able to fire. While these weapons don't typically exist in large numbers in modern military's, the exist in some forms of artillery, tanks, and sniper rifles, such as bolt action rifles. While they used to serve as primary weapons, they now largely have been replaced by semi-automatic weapons. Despite this, bolt action weapons still often play a limited role with sniper rifles. In general, single shot or manually loaded weapons allow for larger rounds in what is otherwise complex mechanisms that may not be able to handle the stress otherwise. Weapon TypesThere are, in general, assault rifles, battle rifles, marksmen weapons, sniper rifles, machine guns, sub-machine guns, heavy machine guns, grenade launchers, pistols and revolvers. Assault rifles, like the M16, Ak-47, and G36, generally are semi-automatic or fully automatic weapons that utilize medium range rounds, at around 1300-2600 joules. They are generally weaker, smaller, less powerful rifle rounds, utilize for their low recoil to allow the weapon to be easier to use, and carry more rounds. Battle rifles are similiar, except they are usually bigger, and utilize much larger full sized cartridges, like the .30-06 or 7.62mm x 51mm NATO rounds, such as in the G3 or FN FAL. Small variants of these are often times referred to as carbines, for their shorter barrel, and therefore shorter over-all length. Marksmen and sniper weapons are essentially weapons designed for accuracy. Since any weapon can be designed for accuracy, and weapon designed for such purposes can be designated as a marksmen of sniper weapon. Since more accurate weapons tend to be of a certain type, they are generally depicted in various manners, but any weapon designed for accurate fire can be considered as such. Marksmen and sniper weapons generally differentiate by marksmen weapons focusing more on rapid accurate fire, while sniper rifles typically maximize for accurate fire, ignoring other typically favorable features on a weapon, such as rapid fire or even ergonomics. Machine guns typically fire rifle rounds, while sub-machine guns typically fire pistol rounds. Both are intended for fully automatic fire, and as a result are generally heavier than pistols or rifles. Sub-machine guns are generally around the size of a rifle, to help handle the stress and recoil of firing pistol rounds, where as machine guns are typically much larger than rifles, to compensate for the problems of firing so many rifle rounds so quickly. While heavy and large, they generally are fundamentally similiar to most rifles, albeit beefier and generally more reliable. Sub-machine guns more or less have a limited range, typically out to about 100 yards, due to the weaker round, although machine guns are typically able to reach out to further ranges, with a full sized rifle round, or 600 yards+
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Posted: Fri Apr 05, 2013 11:44 pm
Pieces of the Firearm
Bolt
A bolt is the part of a firearm that blocks the rear of the chamber while the propellant burns, trapping in the gases and raising and directing the pressure of the expanding gases, but moves out of the way to allow another cartridge or shell to be inserted in the chamber. The bolt is typically loaded by hand, manually, at some point, to load the first round in; with a bolt action, a weapon must be loaded manually every time. With a semi auto or fully automatic weapon, you only must load the round in manually once, and then the bullets become self loading after that, utilizing the recoil of the previous round to load in the next round.
Typically, this is operated by the bolt handle!
Firing pin
A firing pin or striker is a device designed to set off the primer in a cartridge, setting off the gunpowder, and propel the round down the end of the barrel. Typically, the primer is a small part of the over-all cartridge, set off very specifically as to avoid accidents. The firing pin usually ensures the right area is hit, with a certain degree of accuracy, to avoid potential accidents.
Rimfire cartridges, like the .22, don't normally require such accuracy, but most firearms do, for safety reasons.
Receiver
This area essentially houses the working mechanisms of the gun. Usually, gas operated weapons take a small amount of gas from the weapon, through the barrel, and push it down a gas tube, or act on a piston, to help the weapon cycle. Otherwise it is an ordinary recoil operated system, using the backwards expansion of the gases to cycle the weapon and load another round into the chamber, to be fired again.
Barrel
Essentially just a tube to capture gases and propel the bullet. The longer tube captures more gases and directs them, both making the weapon more accurate and usually substantially more powerful; given that a tighter fit results in more captured gases and more power, generally a barrel is slightly smaller than the bullet, as the bullet compresses to fit the barrel (due to the coating and being made of lead), but they are around the same size. Rifling in the barrel gives the bullet a spin and causes it to twist in flight; this twist gives the bullet lateral strength and stabilizes it in flight, as well as makes it harder to deflect. The effect is very similiar to a top, which stays upright so long as it's spinning; with this in mind, the rifling of the gun allows the bullet to stay stabilized, and be much more accurate than it otherwise would be.
Magazine- Magazine Release
The magazine essentially holds the bullet; it's otherwise a standard detachable box magazine. The magazine is capable of being removed, and has a spring with forces the rounds up; the over-all shape of the magazine guides the rounds into the weapon, which allows it to chamber and fire. As soon as the chamber opens, another round is pushed into the weapon from the magazine.
Belt fed weapons usually lack this feature, although their mechanism is essentially the same. A small lever latches on to device on the cartridge, which is connected to a belt, that connects all the bullets; when the lever moves as a result of the weapon cycling, it pulls another bullet into the weapon.
Selector switch and safeties
Selectors are fairly simple, in that they determine if the weapon is ready to fire, or how it will fire. Safe, semi, and auto selectors determine what mode it may fire in, or a burst function.
Charging Handle
The charging handle primes the firing pin, in some weapons, in case the weapon didn't fire correctly. It can be utilized to ensure the next round will fire, or help make sure the weapon feeds correctly without having to open up the weapon and fiddle with it. If this is a common problem on weapons, it can often be added, or be added just for extra security.
Forward Assist
The forward assist helps make sure the round is in the chamber. While this is usually not an issue with most firearms, some slower cycling weapons, or faster ones, need to ensure that the round is firmly seated in the chamber. The forward assist simply allows you to make sure the round is in place, without having to open up the breech and mess with the weapon. While somewhat unnecessary on many guns, it can be prudent to add them in case the weapon would not load properly.
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