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A smoothbore weapon is one that has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.
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A smoothbore weapon is one that has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.
Early firearms had smoothly bored barrels that fired projectiles without significant spin. [1] To minimize inaccuracy-inducing tumbling during flight, their projectiles required an aerodynamically uniform shape, such as a sphere. However, surface imperfections on the projectile and/or the barrel will cause even a sphere to rotate randomly during flight, and the Magnus effect will curve it off the intended trajectory when spinning on any axis not parallel to the direction of travel. [2]
Rifling the bore surface with spiral grooves or polygonal valleys imparts a stabilizing gyroscopic spin to a projectile that prevents tumbling in flight. Not only does this more than counter Magnus-induced drift, but it allows a longer, more streamlined round with greater sectional density to be fired from the same caliber barrel, improving the accuracy, effective range and hitting power.
In the eighteenth century, the standard infantry arm was the smoothbore musket; although rifled muskets were introduced in the early 18th century and had more power and range, they did not become the norm until the middle of the 19th century, when the Minié ball increased their rate of fire to match that of smoothbores. [3]
Artillery weapons were smoothbore until the mid-19th century, and smoothbores continued in limited use until the late 19th century. Early rifled artillery pieces were patented by Joseph Whitworth and William Armstrong in the United Kingdom in 1855. In the United States, rifled small arms and artillery were gradually adopted during the American Civil War. However, heavy coast defense Rodman smoothbores persisted in the US until 1900 due to the tendency of the Civil War's heavy Parrott rifles to burst and lack of funding for replacement weapons.
Some smoothbore firearms are still used.
A shotgun fires multiple, round shot; firing out of a rifled barrel would impart centrifugal forces that result a doughnut-shaped pattern of shot (with a high projectile density on the periphery, and a low projectile density in the interior). While this may be acceptable at close ranges (some spreader chokes are rifled to produce wide patterns at close range) this is not desirable at longer ranges, where a tight, consistent pattern is required to improve accuracy. [4]
Another smoothbore weapon in use today is the 37-mm riot gun, which fires less-lethal munitions like rubber bullets and teargas at short range at crowds, where a high degree of accuracy is not required. [5]
The Steyr IWS 2000 anti-tank rifle is smoothbore. This can help accelerate projectiles and increase ballistic effectiveness. The projectile is a 15.2 mm fin-stabilized discarding-sabot type with armor-piercing capability which the IWS 2000 was specifically designed to fire. It contains a dart-shaped penetrator of either tungsten carbide or depleted uranium, capable of piercing 40 mm of rolled homogeneous armor at a range of 1,000 m, and causing secondary fragmentation.
The cannon made the transition from smoothbore firing cannonballs to rifled firing shells in the mid-19th century. However, to reliably penetrate the thick armor of modern armored vehicles many modern tank guns have moved back to smoothbore. These fire a very long, thin kinetic-energy projectile, too long in relation to its diameter to develop the necessary spin rate through rifling. Instead, kinetic energy rounds are produced as fin-stabilized darts. Not only does this reduce the time and expense of producing rifled barrels, it also reduces the need for replacement due to barrel wear.[ citation needed ]
The armour-piercing gun evolution has also shown up in small arms, particularly the now abandoned U.S. Advanced Combat Rifle (ACR) program. The ACR "rifles" used smoothbore barrels to fire single or multiple flechettes (tiny darts), rather than bullets, per pull of the trigger, to provide long range, flat trajectory, and armor-piercing abilities. Just like kinetic-energy tank rounds, flechettes are too long and thin to be stabilized by rifling and perform best from a smoothbore barrel. The ACR program was abandoned due to reliability problems and poor terminal ballistics.[ citation needed ]
Mortar barrels are typically muzzle-loading smoothbores. Since mortars fire bombs that are dropped down the barrel and must not be a tight fit, a smooth barrel is essential. The bombs are fin-stabilized.
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A rifle is a long-barreled firearm designed for accurate shooting, with a barrel that has a helical pattern of grooves (rifling) cut into the bore wall. In keeping with their focus on accuracy, rifles are typically designed to be held with both hands and braced firmly against the shooter's shoulder via a buttstock for stability during shooting. Rifles are used extensively in warfare, law enforcement, hunting, shooting sports, and crime.
A kinetic energy penetrator (KEP), also known as long-rod penetrator (LRP), is a type of ammunition designed to penetrate vehicle armour using a flechette-like, high-sectional density projectile. Like a bullet or kinetic energy weapon, this type of ammunition does not contain explosive payloads and uses purely kinetic energy to penetrate the target. Modern KEP munitions are typically of the armour-piercing fin-stabilized discarding sabot (APFSDS) type.
A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constructions, including specialized functions such as hunting, target shooting, training, and combat. Bullets are often tapered, making them more aerodynamic. Bullet size is expressed by weight and diameter in both imperial and metric measurement systems. Bullets do not normally contain explosives but strike or damage the intended target by transferring kinetic energy upon impact and penetration.
Armour-piercing ammunition (AP) is a type of projectile designed to penetrate either body armour or vehicle armour.
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.
In firearms, rifling is machining helical grooves into the internal (bore) surface of a gun's barrel for the purpose of exerting torque and thus imparting a spin to a projectile around its longitudinal axis during shooting to stabilize the projectile longitudinally by conservation of angular momentum, improving its aerodynamic stability and accuracy over smoothbore designs.
Terminal ballistics is a sub-field of ballistics concerned with the behavior and effects of a projectile when it hits and transfers its energy to a target.
High-explosive anti-tank (HEAT) is the effect of a shaped charge explosive that uses the Munroe effect to penetrate heavy armor. The warhead functions by having an explosive charge collapse a metal liner inside the warhead into a high-velocity shaped charge jet; this is capable of penetrating armor steel to a depth of seven or more times the diameter of the charge. The shaped charge jet armor penetration effect is purely kinetic in nature; the round has no explosive or incendiary effect on the armor.
A mortar is usually a simple, lightweight, man-portable, muzzle-loaded weapon, consisting of a smooth-bore metal tube fixed to a base plate with a lightweight bipod mount and a sight. They launch explosive shells in high-arcing ballistic trajectories. Mortars are typically used as indirect fire weapons for close fire support with a variety of ammunition.
A driving band or rotating band is a band of soft metal near the base of an artillery shell, often made of gilding metal, copper, or lead. When the shell is fired, the pressure of the propellant swages the metal into the rifling of the barrel and forms a seal; this seal prevents the gases from blowing past the shell, and engages the barrel's rifling to spin-stabilize the shell.
A sabot is a supportive device used in firearm/artillery ammunitions to fit/patch around a projectile, such as a bullet/slug or a flechette-like projectile, and keep it aligned in the center of the barrel when fired. It allows a narrower projectile with high sectional density to be fired through a barrel of much larger bore diameter with maximal accelerative transfer of kinetic energy. After leaving the muzzle, the sabot typically separates from the projectile in flight, diverting only a very small portion of the overall kinetic energy.
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.
The Steyr IWS 2000 is an Austrian single-shot bolt-action anti-materiel rifle produced by Steyr Mannlicher. IWS stands for Infantry Weapon System. Like many anti-tank rifles, it is actually a smoothbore weapon and not a true rifle. This can help accelerate projectiles and increase ballistic effectiveness, but the lack of rifling imparting inertial stability requires the projectile to have stabilizing fins. It is chambered in a 15.2×169 mm armor-piercing fin-stabilized discarding-sabot cartridge, and is the first man-portable rifle to use this type of ammunition.
The Minié ball or Minie ball, is a type of hollow-based bullet designed by Claude-Étienne Minié, inventor of the French Minié rifle, for muzzle-loading rifled muskets. It was invented in 1847 and came to prominence in the Crimean War and the American Civil War, where it was found to inflict significantly more serious wounds than earlier round musket balls. Both the American Springfield Model 1861 and the British Pattern 1853 Enfield rifled muskets, the most common weapons used during the American Civil War, used the Minié ball.
A tank gun is the main armament of a tank. Modern tank guns are high-velocity, large-caliber artilleries capable of firing kinetic energy penetrators, high-explosive anti-tank, and cannon-launched guided projectiles. Anti-aircraft guns can also be mounted to tanks.
A shotgun slug is a heavy projectile made of lead, copper, or other material and fired from a shotgun. Slugs are designed for hunting large game, and other uses, particularly in areas near human population where their short range and slow speed helps increase safety margin. The first effective modern shotgun slug was introduced by Wilhelm Brenneke in 1898, and his design remains in use today. Most shotgun slugs are designed to be fired through a cylinder bore, improved cylinder choke, rifled choke tubes, or fully rifled bores. Slugs differ from round ball lead projectiles in that they are stabilized in some manner.
A rifled musket, rifle musket, or rifle-musket is a type of firearm made in the mid-19th century. Originally the term referred only to muskets that had been produced as a smoothbore weapon and later had their barrels replaced with rifled barrels. The term later included rifles that directly replaced, and were of the same design overall as, a particular model of smoothbore musket.
2A19 or T-12 is a Soviet-designed 100-mm anti-tank gun. It was the first anti-tank gun to adopt a smoothbore barrel, and to introduce modern armor piercing shot, like the APFSDS. It uses long projectiles that are more powerful than its caliber suggests. The T-12 served as the primary towed anti-tank artillery in the Soviet and Bulgarian armies from the early 1960s to the late 1980s.
A muzzle-loading rifle is a muzzle-loaded small arm or artillery piece that has a rifled barrel rather than a smoothbore. The term "rifled muzzle loader" typically is used to describe a type of artillery piece, although it is technically accurate for small arms as well. A shoulder arm is typically just called a "rifle", as almost all small arms were rifled by the time breechloading became prevalent. Muzzle and breechloading artillery served together for several decades, making a clear distinction more important. In the case of artillery, the abbreviation "RML" is often prefixed to the guns designation; a Rifled breech loader would be "RBL", or often just "BL", since smoothbore breechloading artillery is almost nonexistent. A muzzle loading weapon is loaded through the muzzle, or front of the barrel. This is the opposite of a breech-loading weapon or rifled breechloader (RBL), which is loaded from the breech-end of the barrel. The rifling grooves cut on the inside of the barrel cause the projectile to spin rapidly in flight, giving it greater stability and hence range and accuracy than smoothbore guns. Hand held rifles were well-developed by the 1740s. A popularly recognizable form of the "muzzleloader" is the Kentucky Rifle, which was actually developed in Pennsylvania. The American Longrifle evolved from the German "Jäger" rifle.
Armour-piercing fin-stabilized discarding sabot (APFSDS), long dart penetrator, or simply dart ammunition, is a type of kinetic energy penetrator ammunition used to attack modern vehicle armour. As an armament for main battle tanks, it succeeds Armour-Piercing Discarding Sabot (APDS) ammunition, which is still used in small or medium caliber weapon systems.