The SIG KE7 is a light machine gun designed and manufactured in Switzerland in the decade before the Second World War . Although exported, it was never used by the Swiss Army .
41-419: The SIG KE7 is a recoil operated , air cooled light machine gun with tilting bolt. It is fed from a curved box magazine mounted on the underside of the weapon, which holds 25 rounds. A light folding bipod is attached to the perforated barrel jacket, and an additional rear monopod can be fitted. Notable feature of the gun is a very long travel of the bolt carrier (about 6 cm, 2.4 in) before it starts pulling
82-399: A shockwave that spreads out from the impact. The object breaks and excavates into the ground and rock, at the same time spraying material known as impact ejecta. This ejecta is distributed outward from the crater's rim onto the surface as debris; it can be loose material or a blanket of debris, which thins at the outermost regions. Ejecta features are classified based on their distance from
123-400: A barrel to do so. However no one has been able to verify this claim in recent times, although there is another automatic gun that dates from the same year, but its type and method of operation are unknown. Recoil-operation, if it was invented in 1663, would then lie dormant until the 19th century, when a number of inventors started to patent designs featuring recoil operation; this was due to
164-711: A long-recoil–operated shotgun line, the AL-48 , which shares both the original Browning action design, and the "humpbacked" appearance of the original Auto-5. Other weapons based on the Browning system were the Remington Model 8 semi-automatic rifle (1906), the Remington Model 11 & "The Sportsman" model (a model 11 with only a two-shell magazine) shotguns, the Frommer Stop line of pistols (1907), and
205-469: A new shell has been positioned from the magazine. The bolt is released and forced closed by its recoil spring, chambering a fresh round. The long recoil system was invented in the late 19th century and dominated the automatic shotgun market for more than half that century before it was supplanted by new gas-operated designs. While Browning halted production of the Auto-5 design in 1999, Franchi still makes
246-427: A portion of the firearm recoils while inertia holds another portion motionless relative to a mass such as the ground, a ship's gun mount, or a human holding the firearm. The moving and the motionless masses are coupled by a spring that absorbs the recoil energy as it is compressed by the movement and then expands providing energy for the rest of the operating cycle. Since there is a minimum momentum required to operate
287-584: A recoil-operated firearm's action, the cartridge must generate sufficient recoil to provide that momentum. Therefore, recoil-operated firearms work best with a cartridge that yields a momentum approximately equal to that for which the mechanism was optimized. For example, the M1911 design with factory springs is optimized for a 230-grain (15 g) bullet at factory velocity. Changes in caliber or drastic changes in bullet weight and/or velocity require modifications to spring weight or slide mass to compensate. Similarly
328-444: Is an operating mechanism used to implement locked-breech autoloading firearms . Recoil operated firearms use the energy of recoil to cycle the action, as opposed to gas operation or blowback operation using the pressure of the propellant gas. The earliest mention of recoil used to assist the loading of firearms is sometimes claimed to be in 1663 when an Englishman called Palmer proposed to employ either it or gases tapped along
369-513: Is by Alexander Blakely in 1862, who clearly describes using the recoil of a fired cannon to open the breech. In 1864 after the Second Schleswig War , Denmark started a program intended to develop a gun that used the recoil of a fired shot to reload the firearm, though a working model wouldn't be produced until 1888. Later in the 1870s, a Swedish captain called D. H. Friberg patented a design which introduced both flapper-locking and
410-423: Is full of dust and debris that originated from the initial impact. The size of this impact crater along with the ejecta blanket can be used to determine the size and intensity of the impacting object. On earth, these ejecta blankets can be analyzed to determine the source location of the impact. A lack of impact ejecta around the planet Mars 's surface feature Eden Patera was one of the reasons for suspecting in
451-478: Is only applied to heavily recoiling firearms, particularly shotguns. A similar system using inertia operation was then developed by Paolo Benelli in the early 1980s and patented in 1986. With the exception of Sjögren's shotguns and rifles in the early 1900s, all inertia-operated firearms made until 2012 were either made by Benelli or used a design licensed from Benelli, such as the Franchi Affinity. Then
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#1732776132068492-673: Is the toggle bolt design of the Borchardt C-93 and its descendant, the Luger pistol . While the short recoil design is most common in pistols, the very first short-recoil–operated firearm was also the first machine gun , the Maxim gun . It used a toggle bolt similar to the one Borchardt later adapted to pistols. Vladimirov also used the short recoil principle in the Soviet KPV-14.5 heavy machine gun which has been in service with
533-540: The Browning Arms Company introduced the inertia-operated A5 (trademarked as Kinematic Drive) as successor to the long-recoil operated Auto-5 . Both the Benelli and Browning systems are based on a rotating locking bolt, similar to that used in many gas-operated firearms. Before firing, the bolt body is separated from the locked bolt head by a stiff spring. As the shotgun recoils after firing, inertia of
574-475: The Chauchat automatic rifle (1915). The short recoil action dominates the world of centerfire semi-automatic pistols , being found in nearly all weapons chambered for high-pressure pistol cartridges of 9×19mm Parabellum and larger, while low-pressure pistol cartridges of .380 ACP and smaller generally use the blowback method of operation. Short recoil operation differs from long recoil operation in that
615-836: The Chinese Civil War , the Second Sino-Japanese War and the Korean War . Some KE-7 machine guns were also made in other calibres for export to Latin America and Ethiopia . In 1930, examples were provided for trials being run by the British Army to find a replacement for the Lewis gun , although a modified ZB vz. 26 was finally adopted as the Bren gun . Recoil operation Recoil operation
656-446: The barrel also cause all or a portion of the firearm to move in the opposite direction. The result is required by the conservation of momentum such that the ejecta momentum and recoiling momentum are equal. These momenta are calculated by: The barrel is a moving part of the action in recoil-operated firearms. In non-recoil-operated firearms, it is generally the entire firearm that recoils. However, in recoil-operated firearms, only
697-402: The 2010s that it is a collapsed volcanic caldera and not an impact crater. In astrophysics or heliophysics , ejecta refers to material expelled in a stellar explosion as in a supernova or in a coronal mass ejection (CME). Beside material launched by humans into space with a range of launch systems , some instances particularly nuclear produce artificial ejecta, like in the case of
738-468: The Britons Schlund and Arthur. In a long recoil action, the barrel and bolt remain locked together during recoil, compressing the recoil springs. Following this rearward movement, the bolt locks to the rear and the barrel is forced forward by its spring. The bolt is held in position until the barrel returns completely forward during which time the spent cartridge has been extracted and ejected, and
779-490: The Moon or Mercury. Concentric ejecta patterns are characterized by the presence of multiple, circular layers of ejecta surrounding the impact crater. These patterns are commonly observed on icy surfaces, such as the moons of Jupiter and Saturn, and are indicative of the presence of subsurface volatiles, like water or other ices. If enough ejecta are deposited around an impact crater , it can form an ejecta blanket ; this blanket
820-618: The Russian military and Middle Eastern armed forces since 1949. Melvin Johnson also used the short recoil principle in his M1941 Johnson machine gun and M1941 rifle, other rifles using short recoil are LWRCI SMG 45 and LoneStar Future Weapons RM-277R . An alternative design concept for recoil-operated firearms is the inertia operated system, the first practical use of it being the Sjögren shotgun , developed by Carl Axel Theodor Sjögren in
861-452: The action, allowing a wide range of shotshells to be used, from standard to magnum loads, as long as they provide the minimum recoil level to compress the spring. Note that the shotgun must be free to recoil for this to work—the compressibility of the shooter's body is sufficient to allow this movement, but firing the shotgun from a secure position in a rest or with the stock against the ground will not allow it to recoil sufficiently to operate
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#1732776132068902-423: The barrel and bolt recoil together only a short distance before they unlock and separate. The barrel stops quickly, and the bolt continues rearward, compressing the recoil spring and performing the automated extraction and feeding process. During the last portion of its forward travel, the bolt locks into the barrel and pushes the barrel back into battery. The method of locking and unlocking the barrel differentiates
943-509: The barrel and cylinder are affixed to an upper frame which recoils atop a sub-frame. As the upper receiver recoils, the cylinder is advanced and hammer cocked, functions that are usually done manually. Notable examples are the Webley–Fosbery and Mateba . Other autoloading systems are: ejecta Ejecta (from Latin 'things thrown out'; singular ejectum ) are particles ejected from an area. In volcanology , in particular,
984-409: The barrel backwards, in addition to the recoil energy. This boost provides higher rates of fire and/or more reliable operation. This type of mechanism is also found in some suppressors used on short recoil firearms, under the name gas assist or Nielsen device , where it is used to compensate for the extra mass the suppressor adds to the recoiling parts both by providing a boost and decoupling some of
1025-637: The bolt back and extracting the fired case. It gives longer time for the pressure in barrel to drop for easier extraction. The KE7 light machine gun was designed by Pál Király and Gotthard End at the SIG small arms factory in Neuhausen am Rheinfall . Production commenced in 1929, with most weapons being exported to the Republic of China chambered for 7.92×57mm Mauser ammunition. The Chinese government purchased 3,025 from Switzerland between 1928 and 1939, and
1066-405: The bolt body is large enough for it to remain stationary while the recoiling gun and locked bolt head move rearward. This movement compresses the spring between the bolt head and bolt body, storing the energy required to cycle the action. Since the spring can only be compressed a certain amount, this limits the amount of force the spring can absorb, and provides an inherent level of self-regulation to
1107-481: The bolt head, extracts and ejects the cartridge, cocks the hammer, and compresses the return spring. Once the bolt reaches the end of its travel, the return spring provides the force to chamber the next round from the magazine, and lock the bolt closed. Some short-recoil–operated firearms, such as the German MG 42 and MG 3 , use a mechanism at the muzzle to extract some energy from the escaping powder gases to push
1148-404: The early 1900s, a Swedish engineer who was awarded a number of patents for his inertia operated design between 1900 and 1908 and sold about 5,000 automatic shotguns using the system in 1908–1909. In a reversal of the other designs, some inertia systems use nearly the entire firearm as the recoiling component, with only the bolt remaining stationary during firing. Because of this, the inertia system
1189-495: The fact that the integrated disposable cartridge (both bullet and propellant in one easily interchangeable unit) made these designs viable. The earliest mention of recoil operation in the British patent literature is a patent by Joseph Whitworth filed in 1855 which proposed to use recoil to partially open the breech of a rifle, the breech then being manually pulled the rest of the way back by hand. Around this time, an American by
1230-444: The fully automatic recoil operated machine gun. Furthermore, in 1875 a means of cocking a rifle through recoil was patented through the patent agent Frank Wirth by a German called Otto Emmerich. Finally came Maxim's 1883 automatic recoil operated machine gun which introduced the modern age of automatic machine guns. The same forces that cause the ejecta of a firearm (the projectile(s), propellant gas, wad, sabot , etc.) to move down
1271-496: The geological composition of the impacted surface and the projectile that caused the impact. The distribution and morphology of the ejecta blanket can also provide insight into the impact angle and the dynamics of the ejecta emplacement process. Radial and Concentric Ejecta Patterns: Radial ejecta patterns are characterized by the outward distribution of ejecta from the crater in a series of rays or streaks. These rays are often more prominent in craters formed on solid surfaces, such as
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1312-453: The impact crater, the appearance of the ejected material, and the geomorphological characteristics of the terrain. Some common ejecta features include ejecta blankets, radial and concentric ejecta patterns, and secondary craters. Ejecta Blankets: Ejecta blankets are the continuous layer of debris that surrounds the impact crater, thinning outwards from the crater's rim. The composition of the ejecta blanket can provide valuable information about
1353-443: The mechanism. Likewise, care must be exercised when modifying weapons of this type (e.g. addition of extended magazines or ammunition storage on the stock), as any sizable increase in weapon mass can reduce the work done from recoil below that required to cycle the action. As the recoil spring returns to its uncompressed state, it pushes the bolt body backward with sufficient force to cycle the action. The bolt body unlocks and retracts
1394-473: The name of Regulus Pilon is sometimes stated to have patented in Britain a gun that used a limited form of recoil operation. He had three British patents related to firearms around the 1850s to the 1860s; however, all of them refer to a means of dampening recoil in firearms, which wasn't a new idea at the time, rather than true recoil operation. The next to mention recoil operation in the British patent literature
1435-605: The provincial government of Guangdong purchased 200 KE7s with 4,000 magazines in December 1928. In 1933, Liu Xiang funded Huaxing Machine Works' acquisition of machinery for a workshop in Chongqing . From 1933 to 1936, it would produce 6,000 KE7 copies. Three months after the war with Japan began, the workshop would be requisitioned by the Chinese government and produce ZB-26 copies after 1939. The KE7 would be used during
1476-405: The suppressor's mass from the firearm's recoiling parts. Muzzle boosters are also used on some recoil-operated firearms' blank-firing attachments to normalize the recoil force of a blank round (with no projectile) with the greater force of a live round, in order to allow the mechanism to cycle properly. Several revolvers use recoil to cock the hammer and advance the cylinder. In these designs,
1517-408: The surface until the material is expelled rapidly due to the trapped pressure. Sometimes in such an event a lava plug or volcanic neck forms from lava that solidifies inside a volcano's vent, causing heat and pressure to build up to an extreme with no way to escape. When the blockage breaks and cannot sustain itself any longer, a more violent eruption occurs, which allows materials to be ejected out of
1558-451: The term refers to particles including pyroclastic materials ( tephra ) that came out of a volcanic explosion and magma eruption volcanic vent, or crater , has traveled through the air or under water, and fell back on the ground surface or on the ocean floor. Typically in volcanology , ejecta is a result of explosive eruptions . In an explosive eruption, large amounts of gas are dissolved in extremely viscous lava; this lava froths to
1599-402: The use of blank ammunition will typically cause the mechanism not to work correctly, unless a device is fitted to boost the recoil. Recoil-operated designs are broadly categorized by how the parts move under recoil. Long recoil operation is found primarily in shotguns , particularly ones based on John Browning 's Auto-5 action. In 1885 a locked breech, long recoil action was patented by
1640-495: The volcano. Ejecta can consist of: These particles may vary in size; tephra can range from ash (< 1 / 10 inch [0.25 cm]) or lapilli (little stones from 1 / 10 to 2 + 1 ⁄ 2 inches or 0.25 to 6.35 centimetres) to volcanic bombs (>2.5 inches [6.4 cm]). In planetary geology , the term "ejecta" includes debris ejected during the formation of an impact crater . When an object massive enough hits another object with enough force, it creates
1681-711: The wide array of short recoil designs. Most common are the John Browning tilting barrel designs based on either the swinging link and locking lugs as used in the M1911 pistol or the linkless cam design used in the Hi Power and CZ 75 . Other designs are the locking block design found in the Walther P38 and Beretta 92 , rollers in the MG42 , or a rotating barrel used in the Beretta 8000 and others. An unusual variant