A spotting rifle or ranging gun is a small-calibre rifle used as a ranging device for artillery. The ballistics of the spotting rifle are matched to those of the artillery piece, [1] so that if a shot from the spotting rifle lands on the target, it may be assumed that the main weapon will also do so.
Spotting rifles were most commonly used with recoilless rifles as anti-tank artillery, from the 1950s to the 1970s. These weapons are used for direct fire with line-of-sight visibility to the target. As recoilless rifles have a relatively low muzzle velocity and thus a high trajectory, accurate ranging is important [2] An optical sight can measure the bearing to a target, but not easily or accurately measure the range. Optical rangefinders were too large for lightweight portable artillery, and the later development of laser rangefinders would in turn make spotting rifles obsolete.[ citation needed ]
The British BAT series of 120 mm anti-tank recoilless rifles used a variety of sighting systems. The original BAT used a purely optical sight. The MoBAT, a lightweight and more portable version, had a 7.62×51mm NATO Bren light machine gun. [3] The final version, the WOMBAT, used the same American Remington M8C .50 in [4] [5] as the M40 recoilless rifle. Both of these were used as gas-operated semi-automatic rifles. The .50 was not, as often assumed, a development of the .50 M2 machine gun using the 12.7×99mm NATO cartridge, but was a shortened 12.7×76mm cartridge. [6]
Where a vehicle, such as the M50 Ontos, used multiple barrels, spotting rifles were usually provided for each barrel so that each could be accurately boresighted to its own barrel. The Ontos used six barrels with four spotting rifles; two without, to avoid making an already tall vehicle even higher. This provision may have been over-generous, although it did also increase the magazine capacity available for repeated ranging shots. Many photographs of the Ontos in service in Vietnam show it with only two of the spotting rifles installed in their mounts. [7] The Ontos also often carried only four or even two main gun tubes.[ citation needed ]
Perhaps the smallest weapons to use spotting rifles are man-portable shoulder-launched rocket launchers.[ citation needed ]
The British 94mm LAW 80 is a rocket launcher developed as a replacement for the LAW 66 and Carl Gustav to give a more powerful infantry anti-tank capability. This uses a 9 mm rifle with a 5-round magazine and a particularly unusual design of ballistically matched cartridge. [1]
This same spotting rifle (Mk 8 Mod 0) and round was later adopted for the US 83 mm Shoulder-launched Multipurpose Assault Weapon (SMAW). [8]
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A rare few tanks have used spotting rifles, termed a "ranging gun" for ranging their main gun. This was a short-lived use, from the period in the 1950s when the increasingly powerful tank guns (and their reduced capacity for spare ammunition) encouraged a more carefully ranged first shot in the hope of an immediate kill, and the later development of laser rangefinders. [9]
The British Centurion Mk 5/2 with its new 105 mm L7 main gun introduced a ranging gun. [9] [10] This was derived from the M2 Browning design, both the L6 variant of the gun and also its 12.7×99mm ammunition. This ammunition was once again ballistically matched to the main gun. As this was a rather higher velocity round than the recoilless rifles, the case was the same as the M2 and the rounds could be used in either weapon. The enhanced tracer effect of the spotting round was sometimes used in an M2. Mounted in the Centurion it was alongside another conventional co-axial machine gun, the ranging gun being the one in the mantlet closest to the main gun.
The ranging gun was considered a success on the Centurion and was fitted to several marks of it, including retrofitting to earlier models with the 84 mm gun. The same ranging gun principle was later used for the 120 mm gun of the Chieftain. [9] [11] [12] It was considered less successful with the more powerful gun, as the range for accurate ranging was limited to 2,600 yards — beyond this the tracer element burned out and the fall of shot could no longer be seen. As the gun's own range with HESH could be up to 8,700 yards, this represented a serious limitation on performance. Battle planning at this time also saw a need for combat at increasing ranges, from the 2,000 yards expected for the Centurion's vintage out to 3,000 yards and beyond. [9] As soon as they became available, the Chieftain rapidly adopted a laser rangefinder instead.
A later UK light tank using a ranging gun is the FV101 Scorpion, which uses a 7.62mm L43A1 machine gun. [13] This is mounted as a normal co-axial machine gun and may be used as such. it is a development of the standard British L8 Tk MG, used on a number of AFVs and Artillery Pieces. It has an additional barrel bearing that is used to mount the gun. This bearing, rather than mounting by the receiver as for the L8, gives a more consistent point of impact between a cold and hot barrel, which is important for use when ranging.
A recoilless rifle (rifled), recoilless launcher (smoothbore), or simply recoilless gun, sometimes abbreviated to "RR" or "RCL" is a type of lightweight artillery system or man-portable launcher that is designed to eject some form of countermass such as propellant gas from the rear of the weapon at the moment of firing, creating forward thrust that counteracts most of the weapon's recoil. This allows for the elimination of much of the heavy and bulky recoil-counteracting equipment of a conventional cannon as well as a thinner-walled barrel, and thus the launch of a relatively large projectile from a platform that would not be capable of handling the weight or recoil of a conventional gun of the same size. Technically, only devices that use spin-stabilized projectiles fired from a rifled barrel are recoilless rifles, while smoothbore variants are recoilless guns. This distinction is often lost, and both are often called recoilless rifles.
The .50 BMG, also known as 12.7×99mm NATO, and designated as the 50 Browning by the C.I.P., is a .50 in (12.7 mm) caliber cartridge developed for the M2 Browning heavy machine gun in the late 1910s, entering official service in 1921. Under STANAG 4383, it is a standard service cartridge for NATO forces. The cartridge itself has been made in many variants: multiple generations of regular ball, tracer, armor-piercing (AP), incendiary, and saboted sub-caliber penetrator rounds. The rounds intended for machine guns are made into a continuous ammunition belt using metallic links.
Ontos, officially the Rifle, Multiple 106 mm, Self-propelled, M50, was an American light armored tracked anti-tank vehicle developed in the 1950s.
Shoulder-fired missile, shoulder-launched missile or man-portable missile, among other variants, are common slang terms to describe high-caliber shoulder-mounted weapons systems; that is, weapons firing large, heavy projectiles ("missiles"), typically using the backblast principle, which are small enough to be carried by a single person and fired while held on one's shoulder. The word "missile" in this context is used in its original broad sense of a heavy projectile, and encompasses all shells and rockets, guided or unguided. A more formal variant is simply shoulder-fired weapons system and the like.
An anti-tank rifle is an anti-materiel rifle designed to penetrate the armor of armored fighting vehicles, most commonly tanks, armored personnel carriers, and infantry fighting vehicles. The term is usually used for weapons that can be carried and used by one person, but is sometimes used for larger weapons. The usefulness of rifles for this purpose ran from the introduction of tanks in World War I until the Korean War. While medium and heavy tank armor became too thick to be penetrated by rigid projectiles from rifles that could be carried by a single soldier, anti-tank rifles continued to be used against other "soft" targets, though recoilless rifles and rocket-propelled grenades such as the bazooka were also introduced for infantry close-layer defense against tanks.
The Carl Gustaf 8.4 cm recoilless rifle is a Swedish-developed 84 mm (3.3 in) caliber shoulder-fired recoilless rifle, initially developed by the Royal Swedish Army Materiel Administration during the second half of the 1940s as a crew-served man-portable infantry support gun for close-range multi-role anti-armour, anti-personnel, battlefield illumination, smoke screening and marking fire, which has seen great export success around the globe and continues to be a popular multi-purpose support weapon in use by many nations. The Carl Gustaf 84 mm recoilless rifle is a lightweight, low-cost weapon that uses a wide range of ammunition, which makes it extremely flexible and suitable for a wide variety of roles.
The Ordnance Quick-Firing 17-pounder was a 76.2 mm (3 inch) gun developed by the United Kingdom during World War II. It was used as an anti-tank gun on its own carriage, as well as equipping a number of British tanks. Used with the APDS shot, it was capable of defeating all but the thickest armour on German tanks. It was used to "up-gun" some foreign-built vehicles in British service, notably to produce the Sherman Firefly variant of the US M4 Sherman tank, giving British tank units the ability to hold their own against their German counterparts. In the anti-tank role, it was replaced after the war by the 120 mm BAT recoilless rifle. As a tank gun, it was succeeded by the 84 mm 20 pounder.
An anti-tank gun is a form of artillery designed to destroy tanks and other armoured fighting vehicles, normally from a static defensive position. The development of specialized anti-tank munitions and anti-tank guns was prompted by the appearance of tanks during World War I. To destroy hostile tanks, artillerymen often used field guns depressed to fire directly at their targets, but this practice expended too much valuable ammunition and was of increasingly limited effectiveness as tank armor became thicker. The first dedicated anti-tank artillery began appearing in the 1920s, and by World War II was a common appearance in many European armies. To penetrate armor, they fired specialized ammunition from longer barrels to achieve a higher muzzle velocity than field guns. Most anti-tank guns were developed in the 1930s as improvements in tanks were noted, and nearly every major arms manufacturer produced one type or another.
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.
The 3.45 inch RCL was an 88 mm British recoilless weapon, designed by Sir Dennis Burney during the Second World War. Delayed by problems due to breech wear because of gas erosion upon firing, it did not see action, as was hoped, in the Far East, particularly Burma. However, it did lead to the post-war Mobat and Wombat recoilless rifles.
The M40 recoilless rifle is a portable, crew-served 105 mm recoilless rifle made in the United States. Intended primarily as an anti-tank weapon, it could also be employed in an antipersonnel role with the use of an antipersonnel-tracer flechette round. The bore was commonly described as being 106 mm caliber but is in fact 105 mm; the 106 mm designation was intended to prevent confusion with incompatible 105 mm ammunition from the failed M27. The air-cooled, breech-loaded, single-shot rifle fired fixed ammunition and was used primarily from a wheeled ground mount or M92 ground mount. It was designed for direct firing only, and sighting equipment for this purpose was furnished with each weapon, including an affixed M8C .50 cal spotting rifle.
The L2 BAT was a 120 mm calibre recoilless anti-tank rifle used by the British Army. It was also produced in the MOBAT version without a gun shield, and the ConBAT version with a new spotting rifle attachment. The L6 Wombat version was greatly lightened through the use of magnesium alloys hence the name. The Wombat was used by mobile units such as paratroopers and marines. the Wombat was also issued to some TA battalions such as 5th Battalion, The Royal Anglian Regiment
The Type-60 self-propelled 106 mm recoilless gun is a light anti-tank vehicle developed by Japan in the late 1950s. It mounts two M40 106 mm recoilless rifles as its main armament.
The M18 recoilless rifle is a 57 mm shoulder-fired, anti-tank recoilless rifle that was used by the U.S. Army in World War II and the Korean War. Recoilless rifles are capable of firing artillery-type shells at reduced velocities comparable to those of standard cannons, and almost entirely without recoil. The M18 was a breech-loaded, single-shot, man-portable, crew-served weapon. It could be used in both anti-tank and anti-personnel roles. The weapon could be both shoulder fired or fired from a prone position. The T3 front grip doubled as an adjustable monopod and the two-piece padded T3 shoulder cradle could swing down and to the rear as a bipod for the gunner. The most stable firing position was from the tripod developed for the water-cooled Browning M1917 machine gun.
The Model 1968 recoilless gun is a 105-mm antitank weapon developed and employed by Argentina. The weapon has been in active service since 1968 and 150 were still operational with Argentine forces as of 2000. A similar weapon is the Argentine 105-mm Model 1974 FMK-1 recoilless gun.
Contentious I was a British air-portable tank destroyer testbed which came about in the late 50s as part of Project Prodigal, a huge overlapping project aimed at the future generation of British vehicles. The Contentious project is often misattributed the “FV4401” title, but this designation was merely used for an earlier design which was not directly connected to the Contentious I, though lessons learned from the FV4401 were applied to successor vehicles.
Man-portable anti-tank systems are traditionally portable shoulder-launched projectile systems firing heavy shell-type projectiles, typically designed to combat protected targets, such as armoured vehicles, field fortifications and at times even low-flying aircraft.
The Carl Gustaf 20 mm recoilless rifle, service name 20 mm pansarvärnsgevär m/42, meaning "20 mm antitank rifle model 1942", was the first recoilless rifle produced by Carl Gustafs Stads Gevärsfaktori. The weapon had a penetration of just over 4 cm RHA with its standard solid shot armour piercing projectile and quickly became obsolete against modern armour, leading to the development of higher caliber recoilless guns, eventually resulting in the Carl Gustaf 84 mm recoilless rifle in 1948.
