Hang fire refers to an unexpected delay between the triggering of a firearm and the ignition of the propellant. [1] This failure was common in firearm actions that relied on open primer pans, due to the poor or inconsistent quality of the powder, although modern firearms are also susceptible. The delay is usually too brief to be noticed, but can be several seconds. A hangfire should be suspected whenever a firearm fails to fire, but has not clearly malfunctioned.
The ignition train of modern firearms begins with detonation of a small quantity of impact-sensitive primary explosive in a primer in cartridge firearms or in a percussion cap in muzzleloaders. The energy released by this detonation is intended to ignite the propellant charge of gunpowder or smokeless powder. Primary explosives may deteriorate with age so they release less energy; and propellants damaged by moisture or lubricants may require more energy to ignite. These conditions may either delay the ignition sequence or cause a misfire if ignition is completely prevented. [2] While a normal ignition sequence causes the firearm to discharge immediately when the trigger is pulled, a hang fire will be perceived as a click when the hammer falls followed by the loud noise of suddenly expanding gas when the firearm discharges. The delay may be only a fraction of a second or may last for several seconds. [3]
A shooter may interpret the initial click of the hammer fall as an unloaded firearm or a misfire. A hang fire delay of a fraction of a second may be fast enough to correct that misinterpretation before the shooter takes inappropriate action to reload; but a longer delay may allow the shooter time to move the firearm so the muzzle points in a different (and possibly unsafe) direction, or to open the action so the cartridge is no longer confined. Unexpected discharge after the firearm has been moved from the firing position will damage whatever is in front of the muzzle, and large-caliber firearms may injure the shooter during recoil. Unexpected discharge as the action is being opened will allow a portion of the propellant energy to burst the cartridge case and possibly damage the firearm with a risk of injury to the shooter and nearby persons. [4]
The correct procedure is to keep the firearm pointed at a safe target for thirty seconds, then remove the round. This rule is usually not followed in combat, where being without a working firearm is the bigger risk.
The phrase "to hang fire" has come to mean a delay in progressing, for example from one task to another. [5]
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.
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, the correct usage only refers to the projectile.
A muzzleloader is any firearm into which the projectile and the propellant charge is loaded from the muzzle of the gun. This is distinct from the modern designs of breech-loading firearms. The term "muzzleloader" applies to both rifled and smoothbore type muzzleloaders, and may also refer to the marksman who specializes in the shooting of such firearms. The firing methods, paraphernalia and mechanism further divide both categories as do caliber.
Muzzle velocity is the speed of a projectile with respect to the muzzle at the moment it leaves the end of a gun's barrel. Firearm muzzle velocities range from approximately 120 m/s (390 ft/s) to 370 m/s (1,200 ft/s) in black powder muskets, to more than 1,200 m/s (3,900 ft/s) in modern rifles with high-velocity cartridges such as the .220 Swift and .204 Ruger, all the way to 1,700 m/s (5,600 ft/s) for tank guns firing kinetic energy penetrator ammunition. To simulate orbital debris impacts on spacecraft, NASA launches projectiles through light-gas guns at speeds up to 8,500 m/s (28,000 ft/s). FPS and MPH are the most common American measurements for bullets. Several factors, including the type of firearm, the cartridge, and the barrel length, determine the bullet's muzzle velocity.
A centerfire cartridge is a firearm metallic cartridge whose primer is located at the center of the base of its casing. Unlike rimfire cartridges, the centerfire primer is typically a separate component seated into a recessed cavity in the case head and is replaceable by reloading.
Cooking off is unfired weapon ammunition exploding prematurely due to heat in the surrounding environment. The term is used both for detonation of ammunition not loaded into a weapon, and unintended firing of a loaded weapon due to heating.
Caseless ammunition (CL), or rather caseless cartridge, is a configuration of weapon-cartridge that eliminates the cartridge case that typically holds the primer, propellant and projectile together as a unit. Instead, the propellant and primer are fitted to the projectile in another way so that a cartridge case is not needed, for example inside or outside the projectile depending on configuration.
A gun barrel is a crucial part of gun-type weapons such as small firearms, artillery pieces, and air guns. It is the straight shooting tube, usually made of rigid high-strength metal, through which a contained rapid expansion of high-pressure gas(es) is used to propel a projectile out of the front end (muzzle) at a high velocity. The hollow interior of the barrel is called the bore, and the diameter of the bore is called its caliber, usually measured in inches or millimetres.
Internal ballistics, a subfield of ballistics, is the study of the propulsion of a projectile.
A blank is a firearm cartridge that, when fired, does not shoot a projectile like a bullet or pellet, but generates a muzzle flash and an explosive sound like a normal gunshot would. Firearms may need to be modified to allow a blank to cycle the action, and the shooter experiences less recoil with a blank than with a live round. Blanks are often used in prop guns for shooting simulations that have no need for ballistic results, but still demand light and sound effects, such as in historical reenactments, special effects for theatre, movie and television productions, combat training, for signaling, and cowboy mounted shooting. Specialised blank cartridges are also used for their propellant force in fields as varied as construction, shooting sports, and fishing and general recreation.
Smokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to gunpowder. The combustion products are mainly gaseous, compared to around 55% solid products for black powder. In addition, smokeless powder does not leave the thick, heavy fouling of hygroscopic material associated with black powder that causes rusting of the barrel.
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.
This article explains terms used for the British Armed Forces' ordnance (weapons) and ammunition. The terms may have slightly different meanings in the military of other countries.
A slamfire is a discharge of a firearm occurring as a cartridge is being loaded into the chamber. Some firearms are designed to slamfire, but the term also describes a malfunction of self-loading firearms. Shooters accustomed to firearms requiring trigger activation for discharge may be unprepared for a slamfire discharge.
A powder-actuated tool is a type of nail gun used in construction and manufacturing to join materials to hard substrates such as steel and concrete. Known as direct fastening or explosive fastening, this technology is powered by a controlled explosion of a small chemical propellant charge, similar to the process that discharges a firearm.
A squib load, also known as a squib round, pop and no kick, or just a squib, is a firearm malfunction in which a fired projectile does not have enough force behind it to exit the barrel, and thus becomes stuck. This type of malfunction can be extremely dangerous, as failing to notice that the projectile has become stuck in the barrel may result in another round being fired directly into the obstructed barrel, resulting in a catastrophic failure of the weapon's structural integrity.
The following are terms related to firearms and ammunition topics.
Ammunition is the material fired, scattered, dropped, or detonated from any weapon or weapon system. Ammunition is both expendable weapons and the component parts of other weapons that create the effect on a target.
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 propel the projectiles out of the gun barrel.