In firearms and artillery , the primer ( / ˈ p r aɪ m ər / ) is the chemical and/or device responsible for initiating the propellant combustion that will propel the projectiles out of the gun barrel .
100-457: The Ruger SP101 is a series of double-action revolvers produced by the American company Sturm, Ruger & Co. The SP101 is a small frame and all-steel-construction carry revolver, with a five-shot ( .38 Special , .357 Magnum , and 9×19mm Parabellum ); six-shot ( .327 Federal Magnum , and .32 H&R Magnum ); or eight-shot ( .22 LR ) cylinder. The Ruger SP101 was introduced in 1989 as
200-411: A quicker initiation of fire, but compromised by having a longer, heavier trigger pull, which can affect accuracy compared to the lighter, shorter trigger pull of a single-action fire. In a DA/SA semi-automatic pistol , the trigger mechanism functions identically to that of a DA revolver. However, this is combined with the ability of the pistol slide to automatically cock the hammer when firing. Thus,
300-436: A "buffer zone" that prevents the shooter from "jerking the trigger", allowing the remnant pressing force from the finger to be dampened via a "follow-through" motion. Although a perceivable overtravel can be felt as adding to the "creep" of the trigger break, it is not always considered a bad thing by some shooters. An overtravel stop will arrest the motion of the trigger blade and prevent excessive movement. When user releases
400-417: A 20 gr (1.3 g) bullet and making it the world's fastest and most powerful rimfire round in use today. The identifying feature of centerfire ammunition is the metal cup containing the primer inserted into a recess in the center of the base of the cartridge. The firearm firing pin crushes this explosive between the cup and an anvil to produce hot gas and a shower of incandescent particles to ignite
500-477: A cartridge or loading the chamber, the hammer or striker will rest in a partially cocked position. The trigger serves the function of completing the cocking cycle and then releasing the striker or hammer. While technically two actions, it differs from a double-action trigger in that the trigger is not capable of fully cocking the striker or hammer. It differs from single-action in that if the striker or hammer were to release, it would generally not be capable of igniting
600-435: A degree of safety in the field compared to having a conventional, very light trigger. There are two types: single set and double set. Set triggers are most likely to be seen on customized weapons and competition rifles where a light trigger pull is beneficial to accuracy. A single set trigger is usually one trigger that may be fired with a conventional amount of trigger pull weight or may be "set" – usually by pushing forward on
700-427: A firearm of any sort is igniting the propellant. The earliest firearms were hand cannons , which were simple closed tubes. There was a small aperture, the "touchhole", drilled in the closed end of the tube, leading to the main powder charge. This hole was filled with finely ground powder, which was then ignited with a hot ember or torch . With the advent of hand-held firearms, this became an undesirable way of firing
800-453: A gun. Holding a burning stick while trying to pour a charge of black powder carefully down a barrel is dangerous, and trying to hold the gun with one hand while simultaneously aiming at the target and looking for the touchhole makes it very difficult to fire accurately. The first attempt to make the process of firing a small arm easier was the "matchlock". The matchlock incorporated a "lock" (so-called because of its resemblance to door locks of
900-424: A heavier weight and little or no discernible movement. A perceivably slow trigger break is often referred to as a "creep", and frequently described as an unfavorable feature. The trigger overtravel happens immediately after the break and is typically a short distance and can be considered an inertially accelerated motion caused by the residual push of the finger coupled with the sudden decrease in resistance after
1000-423: A hot ember at the burning end. After the gun was loaded and the touchhole primed with powder, the burning tip of the match was positioned so that the lock would bring it into contact with the touchhole. To fire the gun, it was aimed and the trigger pulled. This brought the match down to the touchhole, igniting the powder. With careful attention, the slow-burning match could be kept burning for long periods of time, and
1100-467: A manual safety that additionally may serve to decock the hammer. Some have a facility (generally a lever or button) to safely lower the hammer. As a disadvantage, these controls are often intermingled with other controls such as slide releases, magazine releases, take-down levers, takedown lever lock buttons, loaded chamber indicators, barrel tip-up levers, etc. These variables become confusing and require more complicated manuals-of-arms. One other disadvantage
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#17328013434221200-408: A measured charge of powder and a bullet in one convenient package; the paper also served to seal the bullet in the bore. Still, the source of ignition was handled separately from the cartridge. With the advent of chemical primers, it was not long before several systems were invented with many different ways of combining bullet, powder, and primer into a single package which could be loaded quickly from
1300-613: A mechanical impact. The primer in turn ignites the main propellant, just as with a shock-sensitive or external electric type. Among the advantages this brings is the ability, in an automatic weapon, to control the moment of cartridge ignition partially independently of the mechanical action of the gun. Historically this flexibility was employed by the German Luftwaffe in WW II, in the unusually efficient synchronization gear that enabled machine guns and autocannon to be fired through
1400-482: A much faster lock time. It never became a popular sporting arms system and was discontinued by Remington as a result. Primer-actuated firearms use the energy of primer setback to unlock and cycle the firearm. John Garand developed the system in an unsuccessful bid to replace the M1903 bolt-action rifle in the early 1920s. Garand's prototypes worked well with US military .30-06 ammunition and uncrimped primers, but then
1500-476: A new .17 caliber cartridge based on the .22 WMR, the .17 HMR . The .17 HMR is essentially a .22 WMR cartridge necked down to accept a .17-caliber bullet and is used as a flat-shooting, light-duty varmint round. The .17 HMR was followed up by Hornady's .17 Mach 2, or .17 HM2 in 2003, which is based on a slightly lengthened and necked-down .22 Long Rifle cartridge. Both of these .17 caliber rimfire cartridges have had widespread support from firearms makers, and while
1600-527: A police pistol. These weapons also generally lack any type of external safety. DAO is common among police agencies and for small, personal protection firearms. The primary drawback is that the additional trigger pull weight and travel required for each shot reduces accuracy. Pre-set triggers offer a balance of pull weight, trigger travel, safety, and consistency. Glock popularized this trigger in modern pistols and many other manufacturers have released pre-set striker products of their own. The primary disadvantage
1700-488: A result an external safety is sometimes employed. Double-action triggers provide the ability to fire the gun whether the hammer is cocked or uncocked. This feature is desirable for military, police, or self-defense pistols. The primary disadvantage of any double-action trigger is the extra length the trigger must be pulled and the extra weight required to overcome the spring tension of the hammer or striker. DA/SA pistols are versatile mechanisms. These firearms generally have
1800-419: A simpler, more robust design. The "flintlock", like the wheel-lock, used a flashpan and a spark to ignite the powder. As the name implies, the flintlock used flint rather than iron pyrite. The flint was held in a spring-loaded arm, called the "cock" from the resemblance of its motion to a pecking chicken. The cock rotated through approximately a 90-degree arc and was held in the tensioned, or "cocked" position by
1900-496: A single-action mechanism altogether, more commonly DAO revolvers are modifications of existing DA/SA models, with identical internals, only with access to the hammer prevented, either by covering it with a shroud or by removing the thumb spur. In both cases, the goal is to prevent the possible snagging of the hammer spur on clothing or holster. Due to the imposed limitation in accuracy, the majority of DAO revolvers have been short-barrel, close-range "snub" weapons, where rapidity of draw
2000-425: A source of heat , it could be kept ready for extended periods of time. The covered flashpan also provided some ability to withstand bad weather. Wind, rain, and wet weather would render a matchlock useless, but a wheel-lock that was loaded and waterproofed with a bit of grease around the flashpan could be fired under most conditions. The wheel-lock enjoyed only a brief period of popularity before being superseded by
2100-401: A spring) the hammer/striker, rotating a revolver 's cylinder , deactivating internal safeties , transitioning between different firing modes (see progressive trigger ), or reducing the pull weight (see set trigger ). A single-action (SA) trigger is the earliest and mechanically simplest of trigger types. It is called "single-action" because it performs the single function of releasing
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#17328013434222200-415: A trigger pull to both cock and trip the hammer/striker for every single shot, unlike a DA/SA, which only requires a double-action trigger pull for the first shot (or a typical DA/SA revolver, which can fire single action any time the user wishes but uses double-action as a default). This means that there is no single-action function for any shot, and the hammer or striker always rests in the down position until
2300-421: A trigger. Usually, flintlocks could lock the cock in two positions. The "half-cock" position held the cock halfway back, and used a deep notch so that pulling the trigger would not release the cock. Half-cock was a safety position, used when loading, storing or carrying a loaded flintlock. The "full-cock" position held the cock all the way back and was the position from which the gun was fired. The L-shaped "frizzen"
2400-522: A variety of self-consuming cartridges before acknowledging that the advantages of brass cases far outweighed their one drawback. The three systems of self-contained metallic cartridge ignition which have survived the test of time are the rimfire , the Berdan centerfire primer, and the Boxer centerfire primer. A pinfire firearm cartridge is an obsolete type of brass cartridge in which the priming compound
2500-426: A way to catch the hammer on release; while the other two have three-position safety selectors and a way to capture the hammer on release. In these triggers, the third position activates the pull and release mode, while the center selector position causes the trigger to only drop the hammer when pulled. A set trigger allows a shooter to have a greatly reduced trigger pull (the resistance of the trigger) while maintaining
2600-430: Is a mechanism that actuates the function of a ranged weapon such as a firearm , airgun , crossbow , or speargun . The word may also be used to describe a switch that initiates the operation of other non-shooting devices such as a trap , a power tool , or a quick release . A small amount of energy applied to the trigger leads to the release of much more energy. Most triggers use a small flattened lever (called
2700-445: Is a trigger that must perform the double function of both cocking and releasing the hammer/striker. Such trigger design either has no internal sear mechanism capable of holding the hammer/striker in a still position (so cocking and releasing have to happen in one uninterrupted sequence), or has the whole hammer shrouded and/or with the thumb spur machined off, preventing the user from manipulating it separately. This design requires
2800-504: Is also known as traditional double-action (TDA), as the vast majority of modern "double-action" handguns (both revolvers and semi-automatic pistols ) use this type of trigger instead of "double-action only" (DAO). In simple terms, "double-action" refers to a trigger mechanism that both cocks the hammer and then releases the sear, thus performing two "acts", although it is supposed to describe doing both strictly with one trigger pull only. However, in practice most double-action guns feature
2900-412: Is essential and limited accuracy is already an acceptable compromise. The purpose of a DAO action in a semi-automatic is mostly to avoid the change in trigger pull between the first and subsequent shots that one experiences in a DA/SA pistol, while avoiding the perceived danger of carrying a cocked single-action handgun, although it also avoids having to carry a cocked and loaded pistol, or having to lower
3000-418: Is essentially a firing pin directly loaded to a spring, eliminating the need to be struck by a separate hammer. The firing pin/striker then collides into the cartridge primer positioned ahead of it, which contains shock-sensitive compounds (e.g., lead styphnate ) that sparks to ignite the propellant powder within the cartridge case and thus discharges the projectile . The trapping interface between
3100-420: Is ignited by striking a small pin which protrudes radially from just above the base of the cartridge. Invented by Casimir Lefaucheux in 1828, but not patented until 1835, it was one of the earliest practical designs of a metallic cartridge. However, the protruding pin was vulnerable to damage, displacement and accidental ignition. Moreover, the pin had to be positioned carefully in a small notch when loading, making
Ruger SP101 - Misplaced Pages Continue
3200-404: Is often considered the most critical stage of the trigger pull for achieving good practical accuracy, since it happens just prior to the shot being discharged and can cause some unwanted shakes from the shooter's hand at the instant of firing. Shooter preferences vary; some prefer a soft break with a smooth but discernible amount of trigger travel during firing, while others prefer a crisp break with
3300-427: Is placed in the shell and simply spun around to cover the full extremes of the rim. (For more on the exact process and one set of chemical compounds that have been used successfully, see U.S. patent 1,880,235 , a 1932 Remington Arms patent by James E. Burns.) In the dry state, the primer within the rim becomes impact-sensitive. When the rim is then crushed by the hammer or firing pin, the primer detonates and ignites
3400-424: Is that pulling the trigger a second time after a failure to fire will not re-strike the primer. In normal handling of the firearm, this is not an issue; loading the gun requires that the slide be retracted, pre-setting the striker. Clearing a malfunction also usually involves retracting the slide following the " tap rack bang " procedure. Primer (firearms) In early black powder guns such as muzzleloaders ,
3500-399: Is the difference between the first double-action pull and subsequent single-action pulls. DAO firearms resolve some DA/SA shortcomings by making every shot a double-action shot. Because there is no difference in pull weights, training and practice are simplified. Additionally, the heavier trigger pull can help to prevent a negligent discharge under stress. This is a particular advantage for
3600-432: Is the most popular recreational caliber today because it is inexpensive, relatively quiet, and has very low recoil . While the rimfire priming method is limited due to the thin cases required, it has enjoyed a few resurgences recently. First, it was Winchester's .22 Magnum Rimfire, or .22 WMR in 1959, followed in 1970 by Remington's short-lived 5mm Rimfire , based on Winchester's magnum case. In 2002, Hornady introduced
3700-399: Is to rack the slide, clearing the round and recocking the hammer. While this can be advantageous in that many rounds will fire on being struck a second time, and it is faster to pull the trigger a second time than to cycle the action, if the round fails to fire on the second strike, the user will be forced to clear the round anyway, thus using up even more time than if they had simply done so in
3800-510: Is used in the spotting rifles on the LAW 80 and Shoulder-launched Multipurpose Assault Weapon use a 9mm, .308 Winchester -based cartridge with a .22 Hornet blank cartridge in place of the primer. Upon firing, the Hornet case sets back a short distance, unlocking the action. Primer-actuated cartridges/piston primer cartridges use a primer in the form of a blank to contain the propellant within
3900-484: The American Civil War , as it was simpler and more reliable than the flintlock. The main reason the caplock was so quickly adopted was its similarity to the flintlock and the ease of converting older arms to use percussion-cap ignition; usually, the same lock and barrel could be used with minor changes. The flashpan and frizzen were removed and replaced by a small, hollow horizontal cylinder (drum) screwed into
4000-632: The LeMat , as well as early metallic cartridge revolvers such as the Colt Model 1873 "Single Action Army" (named for its trigger mechanism) and Smith & Wesson Model 3 , all of which required a thumb to cock the hammer before firing. Single-action triggers with manually cocked external hammers lasted a while longer in some break-action shotguns and in dangerous game rifles, where the hunter did not want to rely on an unnecessarily complex or fragile weapon. While single-action revolvers never lost favor in
4100-558: The Smith & Wesson Centennial , the Type 26 Revolver , and the Enfield No. 2 Mk I* and Mk I** revolvers, in which there is no external hammer spur, or which simply lack the internal sear mechanism capable of holding the hammer in the cocked position. A double-action/single-action (DA/SA) trigger is a hybrid design combining the features of both single- and double-action mechanisms. It
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4200-598: The Smith & Wesson Model 27 , S&W Model 60 , the Colt Police Positive , Colt Python , etc. Early double-action revolvers included the Beaumont–Adams and Tranter black-powder muzzleloaders . There are some revolvers that can only be fired in double-action mode (DAO), but that is almost always due to existing double-action/single-action models being modified so that the hammer cannot be cocked manually, rather than from weapons designed that way from
4300-440: The breech of the firearm. This greatly streamlined the reloading procedure and paved the way for semi- and fully automatic firearms. This big leap forward came at a price. It introduced an extra component into each round – the cartridge case - which had to be removed before the gun could be reloaded. While a flintlock, for example, is immediately ready to be reloaded once it has been fired, adopting brass cartridge cases brought in
4400-431: The firing pin , or electrically ignited, primers react chemically to produce heat, which gets transferred to the main propellant charge and ignites it, and this, in turn, propels the projectile. Due to their small size, these primers themselves lack the power to shoot the projectile, but still have enough energy to drive a bullet partway into the barrel — a dangerous condition called a squib load . The first step to firing
4500-473: The kinetic energy from the spring releasing, and a firing pin to eventually strike and ignite the primer. There are two primary types of striking mechanisms – hammer and striker . A hammer is a pivoting metallic component subjected to spring tension so when released will swing forward to strike a firing pin like a mallet hitting a punch / chisel , which then relays the hammer impulse by moving forward rapidly along its longitudinal axis. A striker
4600-632: The trigger blade ) depressed by the index finger , but some weapons such as the M2 Browning machine gun or the Iron Horse TOR ("thumb-operated receiver") use a push-button -like thumb-actuated trigger design, and others like the Springfield Armory M6 Scout use a squeeze-bar trigger similar to the "ticklers" on medieval European crossbows . Although the word "trigger" technically implies the entire mechanism (known as
4700-406: The trigger group ), colloquially it is usually used to refer specifically to the trigger blade. Most firearm triggers are "single-action", meaning that the trigger is designed only for the single function of disengaging the sear , which allows for a spring -tensioned hammer / striker to be released. In "double-action" firearm designs, the trigger also performs the additional function of cocking
4800-507: The US right up until the birth of the semi-automatic pistol , double-action revolvers such as the Beaumont–Adams were designed in Europe before the American Civil War broke out and saw great popularity all through the latter half of the 19th century, with certain numbers being sold in the US as well. While many European and some American revolvers were designed as double-action models throughout
4900-460: The bored-out and tapped flash hole and carrying a "nipple" over which the cap could be fitted. A "hammer" which also had half-cock (for loading and applying the cap) and full-cock positions replaced the cock. When released by pulling the trigger, the hammer would strike the cap, crushing it against the nipple. The percussion cap was a thin metal cup that contained a small quantity of pressure-sensitive explosive, often mercury fulminate . When crushed,
5000-447: The cocked position when it is pulled to the rear and the trigger is not depressed. In a revolver , this means that simply squeezing the trigger when the hammer is lowered will both cock and release it. If the user uses their thumb to pull the hammer to the back, but does not press the trigger, the mechanism will lock the hammer in the cocked position until the trigger is pressed, just like a single action. Firing in double-action mode allows
5100-408: The day) that was actuated by a trigger , originally called a "tricker." The lock was a simple lever which pivoted when pulled and lowered the match down to the touchhole. The match was a slow-burning fuse made of plant fibers that were soaked in a solution of nitrates , charcoal , and sulfur , and dried. This "slow-match" was ignited before the gun was needed, and it would slowly burn, keeping
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#17328013434225200-463: The explosive decomposes into gas. Cartridges for military use require stable priming formulations, so war reserves of small-arms ammunition will dependably function after years of storage. Some machine gun and autocannon cartridges (such as the MG 131 13mm and M61 Vulcan 20mm) utilize an internal electric primer that contains chemicals activated by an externally provided electric charge, as opposed to
5300-512: The explosive would detonate, sending a stream of hot gas down through a hole in the nipple and into the touchhole of the gun to ignite the powder charge. In the process of firing, the cap generally split open and would fall off when the hammer was moved to the half-cock position for loading. The caplock system worked well, and is still the preferred method of ignition for hunters and recreational shooters who use muzzle-loading arms. A small number of caseless cartridges use no primer at all, but
5400-616: The factory. A release trigger releases the hammer or striker when the trigger is released by the shooter, rather than when it is pulled. A binary trigger is a trigger for a semiautomatic firearm that drops the hammer both when the trigger is pulled, and also when it is released. Examples include the AR-15 series of rifles, produced by Franklin Armory, Fostech Outdoors, and Liberty Gun Works. The AR-15 trigger as produced by Liberty Gun Works only functions in pull and release mode, and does not have
5500-421: The first place. The Taurus PT 24/7 Pro pistol (not to be confused with the first-generation 24/7 which was a traditional pre-set) offered this feature starting in 2006. The Walther P99 Anti-Stress is another example. A double-crescent trigger provides select fire capability without the need for a fire mode selector switch. Pressing the upper segment of the trigger produced semi-automatic fire, while holding
5600-458: The flashpan to the spark. The flintlock mechanism was simpler and stronger than the wheel-lock, and the flint and steel provided a good, reliable source of ignition. The flintlock remained in military service for over 200 years, and flintlocks are still made today for historical re-enactments and muzzle-loading target competition, and for hunters who enjoy the additional challenge that the flintlock provides. The next major leap in ignition technology
5700-481: The hammer from accidentally dropping, or a " decocker " – a lever that safely and gently drops the hammer (i.e. decocks the gun ) without fear of the gun firing. The latter is the more popular because, without a decocker, the user is forced to lower the hammer by hand onto a loaded chamber, with all of the attendant safety risks that involves, to return the gun to double-action mode. Revolvers almost never feature safeties, since they are traditionally carried un-cocked, and
5800-430: The hammer is manually lowered again. This gives the positive aspects of a single-action trigger without the need to carry "cocked and locked" (with a loaded chamber and cocked hammer), or with an empty chamber, which requires the user to chamber a round before firing. A potential drawback of a DA/SA weapon is that the shooter must be comfortable dealing with two different trigger pulls: the longer, heavier DA first pull and
5900-656: The hammer on a loaded chamber, if one only fires a partial magazine. A good example of this action in a semi-automatic is the SIG Sauer DAK trigger, or the DAO action of the Sig P250 . For striker-fired pistols such as the Taurus 24/7 , the striker will remain in the rest position through the entire reloading cycle. This term applies most often to semi-automatic handguns; however, the term can also apply to some revolvers such as
6000-684: The hammer requires the user to physically cock it prior to every shot; unlike a DA/SA gun, which cocks itself every time the slide is cycled. There are many examples of DA/SA semi-automatics, the Little Tom Pistol being the first, followed up by the Walther PPK and Walther P38 . Modern examples include weapons such as the Beretta 92 , among others. Almost all revolvers that are not specified as single-action models are capable of firing in both double- and single-action mode, for example,
6100-424: The hammer – and there are many designs where the trigger is used for a range of other functions. Firearms use triggers to initiate the firing of a cartridge seated within the gun barrel chamber . This is accomplished by actuating a striking device through a combination of mainspring (which stores elastic energy ), a trap mechanism that can hold the spring under tension , an intermediate mechanism to transmit
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#17328013434226200-504: The hammer/striker (and nothing else), while the hammer/striker must be cocked by separate means. Almost all single-shot and repeating long arms (rifles, shotguns , submachine guns , machine guns, etc.) use this type of trigger. The "classic" single-action revolver of the mid-to-late 19th century includes black powder caplock muzzleloaders such as the Colt 1860 "Army" Model , and Colt 1851 "Navy" Model , and European models like
6300-465: The high-tech, high-velocity .17 caliber jacketed bullets make the .17 Rimfire cartridges quite a bit more expensive than the .22 caliber versions, they are excellent for shorter-range shooting and still far less expensive than comparable centerfire cartridges. In 2013, Winchester released the .17 Winchester Super Magnum , which utilizes the larger case of the long-obsolete .25 Stevens allowing for velocities approaching 3,000 ft/s (910 m/s) with
6400-468: The late 1930s and early 1940s, Walther introduced the first "double-action" (actually DA/SA hybrid) semi-automatic pistols, the PPK and P.38 models, which featured a revolver-style double-action trigger, allowing the weapon to be carried with a round chambered and the hammer lowered. After the first shot, they would fire subsequent shots like a single-action pistol. These pistols rapidly gained popularity, and
6500-420: The late 19th century, for the first half of the 20th century, all semi-automatic pistols were single-action weapons, requiring the weapon to be carried cocked and loaded with the safety on, or uncocked with an empty chamber ( Colt M1911 , Mauser C96 , Luger P.08 , Tokarev TT , Browning Hi-Power ). The difference between these weapons and single-action revolvers is that while a single-action revolver requires
6600-445: The lower segment of the trigger produced fully automatic fire. Though considered innovative at the time, the feature was eliminated on most firearms due to its complexity. Examples include MG 34 , Kulsprutegevär m/40 automatic rifle , M1946 Sieg automatic rifle , Osario Selectiva, and Star Model Z62 . A progressive , or staged trigger allows different firing rates based on how far it is depressed. For example, when pulled lightly,
6700-443: The main charge within the barrel. As gunpowder will not burn when wet, this made it difficult (or even impossible) to fire these types of weapons in rainy or humid conditions. Modern primers, by contrast, are more specialized and distinct from the main propellant they are designed to ignite. They are of two types, those using shock-sensitive chemicals, and those reliant on chemicals ignited by an electric impulse. In smaller weapons
6800-669: The military changed from a fast-burning gunpowder to a progressive-burning Improved Military Rifle (IMR) powder. The slower pressure rise made the primer-actuated prototypes unreliable, so Garand abandoned the design for a gas-operated rifle that became the M1 Garand . AAI Corporation used a primer piston in a rifle submitted for the SPIW competition. Other rifles to use this system were the Postnikov APT and Clarke carbine as described in U.S. patent 2,401,616 . A similar system
6900-524: The moving propellers of their fighter aircraft with a relatively small compromise in the guns' output of automatic fire. Other countries such as the Soviet Union relied on cruder mechanical systems, which reduced the rate of fire of their guns more severely. Electric priming was also used in the EtronX system developed and sold by Remington for some of its sporting rifles. It was sold as a firearm with
7000-415: The optional ability to cock the hammer separately, reducing the trigger to perform just one action. This is opposed to "double-action only" firearms, which completely lack the capability to fire in single-action mode. In a DA/SA trigger, the mechanism is designed with an internal sear that allows the trigger to both cock and release the hammer/striker when fully pulled, or to merely lock the hammer/striker in
7100-409: The pinfire's use in repeating or self-loading weapons impossible. The pinfire survives today only in a few very small blank cartridges designed as noisemakers and in novelty guns. Rimfire cartridges use a thin brass case with a hollow bulge, or rim, around the back end. This rim is filled during manufacture with an impact-sensitive primer. In the wet state, the primer is stable; a pellet of wet primer
7200-481: The powder charge. Berdan and Boxer primers are used in centerfire cartridges; the primers differ in construction. Various priming mixtures have been used in different sized primers to effect prompt ignition of the powder charge. Particles with relatively high heat capacity are required to promptly ignite smokeless powder deterrent coatings. Some priming explosives decompose into incandescent solids or liquids. Inert ingredients may be heated into incandescent sparks when
7300-479: The powder charge. Rimfire cartridges are usually single-use and normally cannot be reloaded. Also, since the rim must be thin enough to be easily crushed, the peak pressure possible in the case is limited by the strength of this thin rim. Rimfire cartridges originally were available in calibers up to 1 in (25 mm) caliber, however, all but the .22 in (5.6 mm) calibers and smaller eventually became obsolete. The .22 Long Rifle , also fired in pistols ,
7400-574: The primary propellant is ignited using an externally provided electric charge, such as with the Voere VEC-91 and the O'Dwyer VLe. This is not to be confused with an electrically ignited internal primer (see below). Chemical primers, advanced metallurgy and manufacturing techniques all came together in the 19th century to create an entirely new class of firearm — the cartridge arm. Flintlock and caplock shooters had long carried their ammunition in paper cartridges , which served to hold
7500-572: The primer is usually of the first type and integrated into the base of a cartridge. Examples include handgun cartridges , rifle cartridges , and shotgun shells . Larger artillery pieces in contrast typically use electric priming. In artillery the primers are frequently a separate component, placed inside the barrel to the rear of the main propellant charge—but there are other examples of guns, including for example some automatic weapons, designed to shoot cartridges with integral electric primers. Upon being struck with sufficient force generated by
7600-399: The primer was essentially the same chemical as the main propellant (albeit usually in a finer-powdered form), but poured into an external flash pan , where it could be ignited by an ignition source such as a slow match or a flintlock , though some muzzleloaders have primers like cap gun caps. This external powder was connected through a small opening at the rear of the gun barrel that led to
7700-553: The primer. Examples of pre-set strikers are the Glock , Smith & Wesson M&P , Springfield Armory XD -S variant (only), Kahr Arms , FN FNS series and Ruger SR series pistols. This type of trigger mechanism is sometimes referred to as a Striker Fired Action or SFA. Examples of pre-set hammers are the Kel-Tec P-32 and Ruger LCP pistols. Pre-set hybrid triggers are similar to a DA/SA trigger in reverse. The first pull of
7800-437: The problems of extraction and ejection. The mechanism of a modern gun not only must load and fire the piece, but also must remove the spent case, which may require just as many moving parts. Many malfunctions involve this process, either through failure to extract a case properly from the chamber or by allowing it to jam the action. Nineteenth-century inventors were reluctant to accept this added complication and experimented with
7900-549: The sear reaches the point of release, which is described as resembling the breaking of rigid materials when the strength fails under stress . The actuation force required to overcome the sear resistance during the break is known as the trigger weight , which is usually measured with a force gauge in newtons in SI units , or alternatively kilograms or grams in metric units, and pounds and/or ounces in US customary units . The break
8000-401: The set trigger, and then pulling the firing trigger. A double set, double phase trigger can be operated as a standard trigger if the set trigger is not pulled, or as a set trigger by first pulling the set trigger. Double set, double phase triggers offer the versatility of both a standard trigger and a set trigger. Pre-set strikers and hammers apply only to semi-automatic handguns. Upon firing
8100-433: The shorter, lighter subsequent SA pulls. The difference between these trigger pulls can affect the accuracy of the crucial first few shots in an emergency situation. Although there is little need for a safety on a DA/SA handgun when carrying it loaded with the hammer down, after the first shots are fired, the hammer will be cocked and the chamber loaded. Thus, most DA/SA guns either feature a conventional safety that prevents
8200-406: The shortest, lightest, and smoothest pull available. The pull is also consistent from shot to shot so no adjustments in technique are needed for proper accuracy. On a single-action revolver, for which the hammer must be manually cocked prior to firing, an added level of safety is present. On a semi-automatic, the hammer will be cocked and made ready to fire by the process of chambering a round, and as
8300-617: The smaller-frame counterpart to the GP100 . Together, these revolvers replaced Sturm, Ruger & Co's long-standing staple in the American firearms market, the Ruger Security-Six series revolvers. A 9 mm version was available until its discontinuation around 1998 but was later re-released in early 2018. A basic .22 LR version was also available until 2003 while a redesigned version was introduced in 2011. and all 9mm cartridges Trigger (firearms)#Double-action A trigger
8400-404: The takeup. Setting the takeup travel (also known as the first stage) to near zero essentially makes the trigger a single-stage trigger. Some single-stage triggers (e.g., Glock Safe Action trigger, Savage AccuTrigger ) have an integral safety with a noticeable spring resistance that can functionally mimic a two-stage trigger. The trigger break is named for the sudden loss of resistance when
8500-411: The traditional single-action-only pistols rapidly lost favor, although they still retain a dedicated following among enthusiasts. Today, a typical revolver or semi-automatic pistol is a DA/SA one, carried in double-action mode but firing most of its shots in single-action mode. A double-action trigger, also known as double-action only (DAO) to prevent confusion with the more common hybrid DA/SA designs,
8600-401: The trigger and the hammer/striker is typically referred to as the sear surface. Variable mechanisms will have this surface directly on the trigger and hammer or have separate sears or other connecting parts. The trigger pull can be divided into three mechanical stages: When considering the practical accuracy of a firearm, the trigger takeup is often considered the least critical stage of
8700-414: The trigger break. It can be a very critical factor for accuracy because shaking movements during this phase may precede the projectile leaving the barrel and is especially important with firearms with long barrels, slow projectiles and heavy trigger weights, where the more significant resistance drop can make the trigger finger overshoot and shake in an uncontrolled fashion. Having some overtravel provides
8800-409: The trigger is pre-set. If the striker or hammer fail to discharge the cartridge, the trigger may be pulled again and will operate as a double-action only (DAO) until the cartridge discharges or the malfunction is cleared. This allows the operator to attempt a second time to fire a cartridge after a misfire malfunction, as opposed to a single-action, in which the only thing to do if a round fails to fire
8900-479: The trigger is tasked to perform, a.k.a. the trigger action (not to be confused with the action of the whole firearm , which refers to all the components that help handle the cartridge, including the magazine , bolt , hammer and firing pin / striker , extractor and ejector in addition to the trigger). While a trigger is primarily designed to set off a shot by releasing the hammer/striker, it may also perform additional functions such as cocking (loading against
9000-431: The trigger pull begins. With semi-automatics, this means that unlike DA/SA weapons, the hammer does not remain cocked after the first round is fired, and every shot is in double-action mode. With revolvers, this means that one does not have the option of cocking the gun before shooting and must always shoot it in double action mode. Although there have been revolvers that were designed with trigger mechanisms totally lacking
9100-409: The trigger pull. Often triggers are classified as either single-stage or two-stage based on the takeup. A single-stage trigger is often called direct trigger and is popular on hunting rifles. A two-stage trigger is often called pressure trigger and is popular on competition rifles. Some fully adjustable triggers can be adjusted to function as either a single-stage or two-stage trigger by adjusting
9200-425: The trigger, and it travels to its resting position. On semiauto firearms the movement eventually passes by reset position where trigger-disconnector mechanism resets itself to its resting state, in which pulling the trigger releases the sear. The reset event does not occur in double action firearms and in full auto firearms. There are numerous types of trigger designs, typically categorized according to which functions
9300-514: The trigger, or by pushing forward on a small lever attached to the rear of the trigger. This takes up the trigger slack (or "take-up") in the trigger and allows for a much lighter trigger pull. This is colloquially known as a hair trigger . A double set trigger achieves the same result, but uses two triggers: one sets the trigger and the other fires the weapon. Double set triggers can be further classified into two different phases. A double set, single phase trigger can only be operated by first pulling
9400-404: The use of the lock mechanism made fairly accurate fire possible. The next revolution in ignition technology was the "wheel-lock". It used a spring-loaded, serrated steel wheel which rubbed against a piece of iron pyrite , similar to a modern lighter . A key was used to wind the wheel and put the spring under tension. Once tensioned, the wheel was held in place by a trigger. When the trigger
9500-485: The user to manually cock the hammer before each firing, a single-action semi-automatic pistol only requires manual cocking for the first shot, after which the slide will reciprocate under recoil to automatically recock the hammer for a next shot, and is thus always cocked and ready unless the user manually decocks the hammer, encounters a misfiring cartridge , or pulls the trigger on an empty chamber (for older weapons lacking "last round bolt hold open" feature). In
9600-416: The weapon can be carried with the hammer down on a loaded chamber, reducing perceived danger of carrying a single-action semi-automatic. When the user is ready to fire, simply pulling the trigger will cock and release the hammer in double action mode. When the weapon fires, the cycling slide automatically cocks the hammer to the rear, meaning that the rest of the shots fired will be in single-action mode, unless
9700-416: The weapon will fire a single shot. When depressed further, the weapon fires at a fully automatic rate. Examples include FN P90 , Jatimatic , CZ Model 25 , PM-63 , BXP , F1 submachine gun , Vigneron submachine gun , Wimmersperg Spz-kr , and Steyr AUG . Each trigger mechanism has its own merits. Historically, the first type of trigger was the single-action. This is the simplest mechanism and generally
9800-459: Was pulled, the serrated edge of the steel rubbed against the pyrite, generating sparks . These sparks were directed into a pan, called the " flash pan ", filled with loose powder which led into the touchhole. The flashpan usually was protected by a spring-loaded cover that would slide out of the way when the trigger was pulled, exposing the powder to the sparks. The wheel-lock was a major innovation — since it did not rely on burning material as
9900-410: Was the invention of the chemical primer, or "cap", and the mechanism which used it, called the "caplock". Percussion ignition was invented by Scottish clergyman Rev. Alexander John Forsyth in 1807 but needed further refinements before it was gradually accepted in the 1820s to 1830s. By the middle of the 19th century, the percussion or caplock system was well established. It was adopted by both sides in
10000-408: Was the other half of the flintlock's ignition system. It served as both a flashpan cover and a steel striking surface for the flint. The frizzen was hinged and spring-loaded so that it would lock in the open or closed position. When closed, the striking surface was positioned so that the flint would strike at the proper angle to generate a spark. The striking flint would also open the frizzen , exposing
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