Lock time

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A firing pin and firing pin spring, whose design can greatly affect the lock time of a firearm. Pistol firing pin.JPG
A firing pin and firing pin spring, whose design can greatly affect the lock time of a firearm.

Lock time or action time refers to the time interval (often measured in milliseconds) from when the trigger of a firearm is activated until the firing pin strikes the primer, and depends on the design of the firing mechanism. A long lock time increases the probability of the shooter pulling the sights away from the target before the bullet has left the barrel, a common shooter error which can lead to poor hits or even misses. Shooters can therefore tend to experience better precision using firearms with a shorter lock time, and short lock times are especially sought after for shooting competitions which require high precision on small targets from unstable positions, such as the standing offhand position.

Contents

Measuring lock time

The lock time can be measured electronically, but is often instead calculated mathematically by the manufacturer.[ citation needed ] Important mathematical design parameters taken into consideration is the spring constant (stiffness), firing pin weight as well as the weight of any other moving parts and length of movement.

The lock time of conventional bolt-action rifles is usually around 2.6 to 9.0 milliseconds. [1] For example, the SIG Sauer 200 STR/SSG 3000 has a relatively short lock time of 2.4 ms. [2] Firearm mechanisms utilizing a hammer are known for having long lock times since the hammer becomes an extra moving part contributing to a longer lock time. For instance, the mil-spec AR-15 and HK416 triggers have a lock time around 10 ms. [3] Firearms with an electric primer can reach lock times close to zero milliseconds.

Lock time examples
Manufacturer and modelLock time
milliseconds
Rößler Titan 3, 6, 16 and Alpha [4] 1.6 ms
Savage 10 AccuTrigger [5] 1.6 ms
Anschütz 1827 Fortner [6] 1.7 ms
Sig Sauer 200 STR [2] 2.4 ms
Remington 700 (short action) [5] 2.6 ms
Winchester Model 70 [6] 3 ms
Remington 700 (long action) [5] [7] 3 to 3.2 ms
Ruger M77 [6] 3.6 ms
M1917 Enfield [6] 4 to 5 ms
Mauser M98 [6] 4 to 5 ms
M1903A Springfield [5] [8] 5.7 to 6.5 ms
Lee–Enfield [9] 8 to 9 ms
AR-15/M4/HK416 [3] approximately 10 ms

Improvement of lock time

Aftermarket part kits are available for several production rifles under names such as known as "speedlock". These kits reduce the lock time compared to the factory rifle by using a lighter firing pin and more powerful springs. While ordinary firing pins are usually made of steel, speedlock firing pins are often either made of titanium or a mix of steel and aluminium, which in some cases can reduce the weight of the new firing pin to near half of the original. More powerful springs are used to further increase the firing pin velocity for further decreasing the lock time, as well as increase reliability since the new firing pin has less mass. On hammer fired firearms, a more lightweight hammer and a more powerful hammer spring can also shorten the lock time, but a hammer fired firearm will still have a noticeably longer lock time than mechanisms without a hammer. [5]

Electronic trigger

Olympic champion Jin Jong-oh with his Steyr LP10E match air pistol featuring an electronic trigger system competing during the 2012 Olympics KOCIS London Korea Jinjongoh Shooting 12 (7683324116).jpg
Olympic champion Jin Jong-oh with his Steyr LP10E match air pistol featuring an electronic trigger system competing during the 2012 Olympics

To reduce lock time, electronic trigger systems can sometimes be fitted instead of mechanical trigger systems. Electronic trigger systems are mostly found in high-end match arms and can reduce action time by about 90% or one order of magnitude. [10] At very low lock times the dwell time of the bullet or pellet becomes the most influential element. The lock time for an electronic firing circuit with electric ignition of a cartridge can be expected to be around 27 microseconds (0.027 milliseconds). Remington's Model 700 EtronX electronic firing circuit achieves a two orders of magnitude reduction compared to the standard Remington 700 rifle mechanical trigger mechanism. [11]

Not only lock time determines how long it takes from when the trigger has been activated until the bullet has left the barrel. Both firearm and ammunition design impacts the time until ignition, time until maximum chamber pressure is reached, and the time the bullet spends traveling through the barrel. These can be summed up chronologically as follows:

  1. Lock time: The time from when the trigger is activated until the firing pin hits the primer.
  2. Ignition time: [12] The time from the firing pin has hit the primer and until the powder has started to burn in such a way that pressure has formed inside the cartridge (reliable ignition and a consistent ignition time is sought after for both safety and precision.).
  3. Time until maximum pressure: The time from when pressure has been created until maximum pressure is reached.
  4. Barrel time: [12] The total time the projectile spends traveling through the barrel. A "faster" cartridge in a short barrel can decrease the barrel travel time, thereby increasing precision.

Point 2, 3, and 4 describe the time from start of ignition until the bullet leaves the barrel, and can be summarized as the bullet dwell time. [13] In most modern fullbore centerfire rifle cartridges the total dwell time lies around 1.0 to 1.5 milliseconds, while the slower .22 Long Rifle round has a dwell time of around 2.3 milliseconds when fired from a smallbore biathlon rifle. [14]

See also

Related Research Articles

<span class="mw-page-title-main">Firearm</span> Gun for an individual

A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries.

Handloading, or reloading, is the practice of making firearm cartridges by assembling the individual components, rather than purchasing mass-assembled, factory-loaded ammunition.

<span class="mw-page-title-main">Single-shot</span> Firearm that holds one round of ammunition

Single-shot firearms are firearms that hold only a single round of ammunition, and must be reloaded manually after every shot. The history of firearms began with single-shot designs, then multi-barreled designs appeared, and eventually many centuries passed before multi-shot repeater designs became commonplace.

<span class="mw-page-title-main">Percussion cap</span> Ignition source in a type of firearm mechanism

The percussion cap or percussion primer, introduced in the early 1820s, is a type of single-use percussion ignition device for muzzle loader firearm locks enabling them to fire reliably in any weather condition. This crucial invention gave rise to the cap lock mechanism or percussion lock system using percussion caps struck by the hammer to set off the gunpowder charge in percussion guns including percussion rifles and cap and ball firearms. Any firearm using a caplock mechanism is a percussion gun. Any long gun with a cap-lock mechanism and rifled barrel is a percussion rifle. Cap and ball describes cap-lock firearms discharging a single bore-diameter spherical bullet with each shot.

<span class="mw-page-title-main">Cartridge (firearms)</span> Ammunition consisting of a casing, projectile, propellant, and primer

A cartridge or a round is a type of pre-assembled firearm ammunition packaging a projectile, a propellant substance and an ignition device (primer) within a metallic, paper, or plastic case that is precisely made to fit within the barrel chamber of a breechloading gun, for the practical purpose of convenient transportation and handling during shooting. Although in popular usage the term "bullet" is often informally used to refer to a complete cartridge, it is correctly used only to refer to the projectile.

<span class="mw-page-title-main">Action (firearms)</span> Functional mechanism of breech-loading

In firearms terminology, an action is the functional mechanism of a breech-loading firearm that handles the ammunition cartridges, or the method by which that mechanism works. Actions are technically not present on muzzleloaders, as all those are single-shot firearms with a closed off breech with the powder and projectile manually loaded from the muzzle. Instead, the muzzleloader ignition mechanism is referred to as the lock.

<span class="mw-page-title-main">Lever action</span> Type of firearm action

Lever-action is a type of action for repeating firearms that uses a manually operated cocking handle located around the trigger guard area that pivots forward to move the bolt via internal linkages, which will feed and extract cartridges into and out of the chamber, and cock the firing pin mechanism. This contrasts to other type of repeating actions such as the bolt-action, pump-action, semi-automatic, or automatic/selective-fire actions. A firearm using this operating mechanism is colloquially referred to as a levergun.

Electronic firing refers to the use of an electric current to fire a cartridge instead of a centerfire primer or rimfire primer.

<span class="mw-page-title-main">Remington Model 700</span> Bolt action rifle

The Remington Model 700 is a series of bolt-action centerfire rifles manufactured by Remington Arms since 1962. It is a development of the Remington 721 and 722 series of rifles, which were introduced in 1948. The M24 and M40 military sniper rifles, used by the US Army and Marine Corps, respectively, are both based on the Model 700 design.

Blowback is a system of operation for self-loading firearms that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gas created by the ignition of the propellant charge.

<span class="mw-page-title-main">Accurizing</span> Process of improving the accuracy and precision of a gun

Accurizing is the process of improving the accuracy and precision of a gun.

<span class="mw-page-title-main">Lock (firearm)</span>

The lock of a firearm is the mechanism used to initiate firing. It is a historical term, in that it generally refers to such mechanisms used in muzzle-loading and early breech-loading firearms. Side-lock refers to the type of construction, in which the individual components of the mechanism are mounted either side of a single plate. The assembly is then mounted to the stock on the side of the firearm. In modern firearm designs, the mechanism to initiate firing is generally constructed within the frame or receiver of the firearm and is referred to as the firing or trigger mechanism.

<span class="mw-page-title-main">Kammerlader</span> Breech-loading rifle

The Kammerlader, or "chamber loader", was the first Norwegian breech-loading rifle, and among the first breech loaders adopted for use by an armed force anywhere in the world. A single-shot black-powder rifle, the kammerlader was operated with a crank mounted on the side of the receiver. This made it much quicker and easier to load than the weapons previously used. Kammerladers quickly gained a reputation for being fast and accurate rifles, and would have been a deadly weapon against massed ranks of infantry.

Thompson/Center Arms was an American firearms company based in Springfield, Massachusetts. The company was best known for its line of interchangeable-barrel, single-shot pistols and rifles. Thompson/Center also manufactures muzzle-loading rifles and was credited with creating the resurgence of their use in the 1970s.

<span class="mw-page-title-main">Break action</span>

Break action is a type of firearm action in which the barrel or barrels are hinged much like a door and rotate perpendicularly to the bore axis to expose the breech and allow loading and unloading of cartridges. A separate operation may be required for the cocking of a hammer to fire the new round. There are many types of break-action firearms; break actions are universal in double-barrelled shotguns, double-barrelled rifles, combination guns, and are also common in single shot pistols, rifles, shotguns, and can also be found in flare guns, grenade launchers, air guns, and some older revolver designs. They are also known as hinge-action, break-open, break-barrel, break-top, or, on old revolvers, top-break actions.

<span class="mw-page-title-main">Cylinder (firearms)</span> Cylindrical revolver part that holds rounds

In firearms, the cylinder is the cylindrical, rotating part of a revolver containing multiple chambers, each of which is capable of holding a single cartridge. The cylinder rotates (revolves) around a central axis in the revolver's action to sequentially align each individual chamber with the barrel bore for repeated firing. Each time the gun is cocked, the cylinder indexes by one chamber. Serving the same function as a rotary magazine, the cylinder stores ammunitions within the revolver and allows it to fire multiple times before needing to reload.

The following are terms related to firearms and ammunition topics.

A firearm malfunction is the failure of a firearm to operate as intended for causes other than user error. Malfunctions range from temporary and relatively safe situations, such as a casing that did not eject, to potentially dangerous occurrences that may permanently damage the gun and cause injury or death. Improper handling of certain types of malfunctions can be very dangerous. Following gun safety rules can prevent firearm malfunctions, and limit the damage inflicted by them if they do occur. Proper cleaning and maintenance of a firearm play a big role in preventing malfunctions.

In firearms and artillery, the primer is the chemical and/or device responsible for initiating the propellant combustion that will push the projectiles out of the gun barrel.

<span class="mw-page-title-main">Anschütz 1827 Fortner</span> Type of biathlon rifle

Anschütz 1827 Fortner is a straight-pull action biathlon rifle designed by Peter Fortner junior and produced in cooperation with J. G. Anschütz. The rifle has been dominant in the sport of biathlon since the late 1980s, and is the current sport standard. It is estimated to be used by 97% of biathlon competitors worldwide. About 7000 had been manufactured by 2007.

References

  1. Tubb Precision Speedlock Firing Pin - Rem 700 Short Action
  2. 1 2 dfs.no - SigSauer - Produktbeskrivelse«Slagtid på tennstempel er 2,4 ms»
  3. 1 2 "Geissele Hi-Speed National Match Trigger manual" (PDF). Archived from the original (PDF) on 2018-08-07. Retrieved 2018-12-08.
  4. titan6.com - Product Cataloge
  5. 1 2 3 4 5 Locktime by Randy Wakeman
  6. 1 2 3 4 5 Lock time by Bart Bobbitt
  7. Van Zwoll, Wayne (2012). Gun Digest Shooter's Guide to Rifles. Iola: Gun Digest Books. p. 58. ISBN   978-1440230721.
  8. Encyclopedia Of American Gun Design And Performance. Book I Rifles Section "Ignition", page 68
  9. Wadham, Rodger (2012). The 2012 Complete Book on Lee Enfield Accurizing B&W. lullu.com. p. 57. ISBN   978-1471603112.
  10. Lock Time – The Key to an Airgun’s Firing Cycle, http://daystate.com, August 3, 2018
  11. Remington's Model 700 EtronX Centerfire Target Rifle Redefines The Big Bang Theory, By Cliff Gromer, www.popularmechanics.com, Dec 7, 2004
  12. 1 2 Encyclopedia Of American Gun Design And Performance. Book I Rifles Section "Ignition", page 170-171
  13. Petty, Charles E. (2000). "Adjustable Sights". American Handgunner. Archived from the original on 2004-11-21. Retrieved 2007-08-31.
  14. J.G. ANSCHÜTZ GmbH & Co. KG - Biathlon «With the extremely light firing pin with only 4 mm travel this rifle got an extremely short lock time of 4 ms, i. e. that the bullet left the barrel after 4 ms after the shot had been released by the trigger. It is of utmost importance for the shooter that the bullet leaves the barrel as fast as possible after shot release to reduce aiming mistakes.»