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51-481: The Birmingham Gun Barrel Proof House is a weapons proving establishment in Banbury Street, Birmingham , UK. The building was designed by John Horton and consists of a centre bay, emphasised by a segmental parapet, which contains trophies by William Hollins . A Jacobean-style gateway was added in 1883. It is a grade II* listed building. The Proof House (originally The Guardians, Trustee, and Wardens of

102-469: A firearm in order to verify that the firearm is not defective and will not explode on firing. The firearm is inspected after the test, and if it is found to be in sound condition, then it is marked with a "proof mark" to indicate that it has been proofed (not proven ). In many jurisdictions a proof test and valid proof mark are required for the sale of firearms. A "proof round" is an ammunition assembly designed to be used in proof testing; this can use

153-516: A museum of arms and ammunition, and can be visited by prior arrangement. Proof test Proof tests may be performed before a new design or unit is allowed to enter service, or perform additional uses, or to verify that an existing unit is still functional as intended. Cranes and derricks are proof tested when called on for potentially dangerous load levels or high-valued cargoes. Similarly, items which are smaller and more common (rope and cable, slings, shackles and eyes) are nevertheless in

204-538: A semi-monocoque is a hybrid combining a tensile stressed skin and a compressive structure made up of longerons and ribs or frames . Other semi-monocoques, not to be confused with true monocoques, include vehicle unibodies , which tend to be composites, and inflatable shells or balloon tanks , both of which are pressure stabilised. Early aircraft were constructed using frames, typically of wood or steel tubing, which could then be covered (or skinned ) with fabric such as Irish linen or cotton . The fabric made

255-514: A combination of castings and sheet-metal stampings". Single-piece carbon fiber bicycle frames are sometimes described as monocoques; however as most use components to form a frame structure (even if molded in a single piece), these are frames not monocoques, and the pedal-cycle industry continues to refer to them as framesets. The P40DC, P42DC and P32ACDM all utilize a monocoque shell. Various rockets have used pressure-stabilized monocoque designs, such as Atlas and Falcon 1 . The Atlas

306-424: A drilled case is used and the piezo measuring device (transducer) will be positioned at a distance of 25 mm from the breech face when the length of the cartridge case permits that, including limits. When the length of the cartridge case is too short, pressure measurement will take place at a cartridge specific defined shorter distance from the breech face depending on the dimensions of the case. The difference in

357-439: A fine of £5,000 may be levied for selling an unproofed or out-of proof firearm, more if a number of firearms are involved in a transaction. Tampering with, or forging, a proof mark is regarded as even more serious. The Proof House still exists today, largely unchanged in both purpose and construction, although it offers a wider range of services including ammunition testing and firearm accident investigation. The building contains

408-627: A fixed cartridge , a semi-fixed cartridge, or separately loaded projectile, charge and primer. A "proof shot" is a special projectile used in a proof round or other projectile weapons, electromagnetic guns for example. Small arms proof rounds resemble normal cartridges, though they will typically bear special markings to prevent them from being confused for standard cartridges. Large calibre arms, such as artillery , will in general use an inert solid projectile (the proof shot); although water, sand or iron (powder) filled versions can be found for testing recoil systems. For both small arms and heavy weapons,

459-494: A frame. This reduces weight for a given amount of armour. Examples include the German TPz Fuchs and RG-33 . French industrialist and engineer Georges Roy attempted in the 1920s to improve on the bicycle-inspired motorcycle frames of the day, which lacked rigidity. This limited their handling and therefore performance. He applied for a patent in 1926, and at the 1929 Paris Automotive Show unveiled his new motorcycle,

510-406: A fuel tank incorporated into the frame. A monocoque-framed motorcycle was developed by Spanish manufacturer Ossa for the 1967 Grand Prix motorcycle racing season . Although the single-cylinder Ossa had 20 horsepower (15 kW) less than its rivals, it was 45 pounds (20 kg) lighter and its monocoque frame was much stiffer than conventional motorcycle frames , giving it superior agility on

561-413: A minor structural contribution in tension but none in compression and was there for aerodynamic reasons only. By considering the structure as a whole and not just the sum of its parts, monocoque construction integrated the skin and frame into a single load-bearing shell with significant improvements to strength and weight. To make the shell, thin strips of wood were laminated into a three dimensional shape;

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612-471: A proofing pressure of ~65,000 psi, 11,000 psi (~17%) above the standard service pressure. In C.I.P. member states every civil firearm has to be professionally proofed in accredited proof houses before it can be sold to consumers. The proofsign may permit identification of the period of time in which it was used. Some of the signs actually used are: The standard proof test consists of firing two overloaded cartridges that produce 25% more chamber pressure than

663-470: A severely overcharged cartridge , or proof load which is fired through the gun in an armoured testing chamber. This exposes it to pressures far beyond what it would experience in normal service. It is awarded a stamped proof mark if it survives without either being destroyed or suffering damage from the proof load. Larger guns were tested at a shooting range in Bordesley along a railway viaduct; however,

714-399: A solid frame. This becomes obvious when internal pressure is lost and the structure collapses. Monocoque tanks can also be cheaper to manufacture than more traditional orthogrids . Blue Origin's upcoming New Glenn launch vehicle will use monocoque construction on its second stage despite the mass penalty in order to reduce the cost of production. This is especially important when the stage

765-515: A technique adopted from boat hull construction. One of the earliest examples was the Deperdussin Monocoque racer in 1912, which used a laminated fuselage made up of three layers of glued poplar veneer, which provided both the external skin and the main load-bearing structure. This also produced a smoother surface and reduced drag so effectively that it was able to win most of the races it was entered into. This style of construction

816-563: A uniform material. After failed attempts with several large flying boats in which a few components were monocoques, he built the Zeppelin-Lindau V1 to test out a monocoque fuselage. Although it crashed, he learned a lot from its construction. The Dornier-Zeppelin D.I was built in 1918 and although too late for operational service during the war was the first all metal monocoque aircraft to enter production. In parallel to Dornier, Zeppelin also employed Adolf Rohrbach , who built

867-505: Is a French term for "single shell". First used for boats, a true monocoque carries both tensile and compressive forces within the skin and can be recognised by the absence of a load-carrying internal frame. Few metal aircraft other than those with milled skins can strictly be regarded as pure monocoques, as they use a metal shell or sheeting reinforced with frames riveted to the skin, but most wooden aircraft are described as monocoques, even though they also incorporate frames. By contrast,

918-498: Is a further test of a gun after its original proof, which may be necessary when changes are made or due to inadequacy of the original proof. Vehicle systems or entire vehicles may be proof-tested. As failure of an aircraft structure or substructure may be catastrophic, demonstration of designs or of in-service units is performed via proof testing. Failure of sail rigging is no longer as catastrophic, but may still lead to damage, injury and loss of vehicle functions. The leak testing

969-410: Is loaded to a higher than normal service pressure, stressing both the gun barrel and breech during firing. This can be due to a heavy projectile fired using the standard propelling charge, the standard projectile fired with a different propellant type or weight, or combinations of charge and bullet weight to give the required proofing pressure. Minimum proof testing pressures are specified by the owner of

1020-415: Is located .175" behind the shoulder of the case for large diameter (.250") transducers and .150" for small diameter (.194") transducers. For straight cases the centre of the transducer is located one-half of the transducer diameter plus .005" behind the base of the seated bullet. Small transducers are used when the case diameter at the point of measurement is less than .35". Under C.I.P. proof test standards

1071-647: Is often combined with a charge design trial. When running a charge development, or strength of design (SoD), trial, the charge mass and service pressure will gradually be worked up to the required proofing pressure of the weapon system. Readings will be taken of chamber pressure by copper crusher, or piezo electric gauges and velocity by Doppler radar (in-bore or aeroballistic), or photocell counter chronographs . In addition strain and temperature readings may also be recorded. If required, high speed photography (synchroballistic photography, high speed digital stills, head on cine, or flight follower) may also be used. Reproof

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1122-444: Is the proceedings to verify and measure the pneumatic tightness of the produced components. This phase of the industrial process is called leak test or leakage detection Monocoque Monocoque ( / ˈ m ɒ n ə k ɒ k , - k oʊ k / MON -ə-ko(h)k ), also called structural skin , is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word monocoque

1173-464: The Junkers J 1 had appeared as early as 1915, these were not monocoques but added a metal skin to an underlying framework. The first metal monocoques were built by Claudius Dornier , while working for Zeppelin-Lindau. He had to overcome a number of problems, not least was the quality of aluminium alloys strong enough to use as structural materials, which frequently formed layers instead of presenting

1224-729: The Zeppelin-Staaken E-4/20 , which when it flew in 1920 became the first multi-engined monocoque airliner, before being destroyed under orders of the Inter-Allied Commission. At the end of WWI, the Inter-Allied Technical Commission published details of the last Zeppelin-Lindau flying boat showing its monocoque construction. In the UK, Oswald Short built a number of experimental aircraft with metal monocoque fuselages starting with

1275-429: The obturator the same as the shot they are emulating. Crack analysis is often undertaken on large-caliber weapons after testing has been carried out. The proof shot is normally a high-drag projectile since its job is over once it has left the muzzle of the gun. A high-drag projectile is advantageous for two reasons; first, it reduces the impact velocity when fired against an earth or sand backstop, and second, it reduces

1326-405: The vehicle's primary structure , are proof-tested when redesigned, and may be tested at the unit level. Testing involves exposure to higher gauge pressures than design levels, or in some cases, pulling harder vacuum. A firearm's chamber and barrel become pressure vessels for brief periods. In firearm terminology, a proof test is a test wherein a deliberately over-pressured round is fired from

1377-427: The 1920 Short Silver Streak in an attempt to convince the air ministry of its superiority over wood. Despite advantages, aluminium alloy monocoques would not become common until the mid 1930s as a result of a number of factors, including design conservatism and production setup costs. Short would eventually prove the merits of the construction method with a series of flying boats, whose metal hulls didn't absorb water as

1428-494: The Aero-D One, featuring a composite monocoque chassis that weighed only 12 kg (26 lb). An aluminium monocoque frame was used for the first time on a mass-produced motorcycle from 2000 on Kawasaki's ZX-12R , their flagship production sportbike aimed at being the fastest production motorcycle . It was described by Cycle World in 2000 as a "monocoque backbone ... a single large diameter beam" and "Fabricated from

1479-514: The Art-Deco styled 1930 Majestic. Its new type of monocoque body solved the problems he had addressed, and along with better rigidity it did double-duty, as frame and bodywork provided some protection from the elements. Strictly considered, it was more of a semi-monocoque, as it used a box-section, pressed-steel frame with twin side rails riveted together via crossmembers, along with floor pans and rear and front bulkheads. A Piatti light scooter

1530-409: The C.I.P. specified maximum pressure limit for the same cartridge in its commercial version. The standard proof of pistol, revolver and rimfire cartridges is performed with overloaded cartridges that produce 30% more chamber pressure than the C.I.P maximum pressure limit for the same cartridge in its commercial version. There are only two overloaded firings to avoid excessive stress to the arm, especially

1581-743: The Gun Barrel Proof House of the Town of Birmingham) was established in 1813 by an act of Parliament at the request—and expense—of the then prosperous Birmingham gun trade. The corporation was renamed to "The Guardians of the Birmingham Proof House" by the Gun Barrel Proof Act 1855 ( 18 & 19 Vict. c. cxlviii). Its remit was to provide a testing and certification service for firearms in order to prove their quality of construction, particularly in terms of

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1632-419: The barrel which is the main part suffering this overload beside the chamber (when not part of the barrel) and the locking mechanism. After the test, the arm is disassembled by the proof house technicians for nondestructive testing looking for magnetic flux leakage through fluoroscopic lamp in a dark room. Many manufacturers package the casings from a firearm's proof ammunition in a sealed envelope accompanying

1683-416: The cartridge specification, such as C.I.P. or SAAMI for most commercial cartridges or NATO EPVAT testing for appropriate military cartridges. An example proofing round for the .50 BMG (12.7 × 99 mm) is the "cartridge, caliber .50, test, high pressure, M1". This uses the standard-weight .50 BMG M1 round propellant (240 gr of WC860), but a bullet weighing 999 gr (+/- 11 gr). The M1 proof round gives

1734-413: The current legally required standard test benchmark is often also possible for consumers who intend the use their firearms under extreme conditions (hot climates, long strings of shots, etc.). In case a firearm passes such a proof-test a pass mark termed superior proof mark is stamped in every successfully tested firearm. Under SAAMI proof test procedures, for bottlenecked cases the centre of the transducer

1785-419: The expansion of the city centre resulted in the closure of the shooting range. Proof may be rendered invalid if the firearm is damaged or modified significantly; at this point it is described as "out of proof" and must be re-proved before it can be sold or transferred. Note that the correct term for a satisfactorily tested firearm is proved , or proven . There are penalties for non-compliance with proof laws;

1836-420: The firearm so that authorities in C.I.P.-signatory states and civilian purchasers in other countries can conduct an independent examination if they desire. Before the year 2006 the standard test consisted of firing two overloaded cartridges producing 30% more chamber pressure then the C.I.P. specified maximum chamber gas pressure limit for the same cartridge in its commercial version. Voluntarily testing beyond

1887-552: The firearm) or may involve more in-depth examination, at the option of the tester. A proof mark is a mark specific to the manufacturer, importer, or testing facility that is performing the test. It generally takes the form of a stamp that makes an impression in the metal. Since proof marks are unique and nearly universal, they are often used to identify the origins of firearms that lack normal manufacturer's markings, such as military weapons, which are often produced by large numbers of different manufacturers. A small arms proof round

1938-424: The gun is fired remotely and then examined; if undamaged, it is assumed to be safe for normal use and a proof mark is added to the barrel. In the case of revolvers or other multi-chamber firearms, each chamber must be proof tested before the firearm may be marked. Examination of the firearm may be as simple as visually inspecting it (defective components may fail in a spectacular manner, resulting in an explosion of

1989-410: The load path and a failure risk if not tested. Testing generally involves lifting weight or drawing tension equal to or greater than design levels. An overspeed proof test involves physically running the machine at high speed up to the test speed. This may be done during manufacture as an initial proof test. Physical overspeed tests may be periodically undertaken on some machines to verify operation of

2040-495: The location of the pressure measurement gives different results than the C.I.P. standard. The test of a large-caliber weapon system primarily covers the strength of the barrel, breech and recoil systems. The proof shot has to resemble the resistance to motion (bore/rifling friction, shot start pressures, etc.) and profile to the propellant gases that the actual service projectile will give. For this reason, proof shots for APFSDS rounds have fin units and all must have profiles behind

2091-536: The overspeed protection systems. Operation at speeds above the normal operating speed can greatly increase stress levels in rotating parts. Failing flywheels, rotors, etc. may present a shrapnel risk in case of a failure. Historically, swords would be proof tested by impact before issuance- the "British test". Vessels which may be a failure risk, such as utility-scale water towers, chemical-handling equipment, or very-high-pressure storage tanks, may be proof tested. Rocket stage tankage, being high-valued and often

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2142-467: The racetrack. Ossa won four Grands Prix races with the monocoque bike before their rider died after a crash during the 250 cc event at the 1970 Isle of Man TT , causing the Ossa factory to withdraw from Grand Prix competition. Notable designers such as Eric Offenstadt and Dan Hanebrink created unique monocoque designs for racing in the early 1970s. The F750 event at the 1973 Isle of Man TT races

2193-587: The range if no backstop is used. Excessive range can be a very problematic when firing any large-caliber round; safety traces can often exceed the bylaw areas of the firing range, so range reduction is imperative. This is even more of a problem when high velocity, low drag rounds such as APDS or APFSDS are used. Although proof shots are used in the service proof of barrels before use, the vast majority are used in propellant charge design. Proof shot emulating APFSDS rounds are also used in stabilizing-fin SoD trials, which

2244-421: The resistance of barrels to explosion under firing conditions. Such testing prior to sale or transfer of firearms is made mandatory by the Gun Barrel Proof Act 1868 ( 31 & 32 Vict. c. cxiii), which made it an offence to sell, offer for sale, transfer, export or pawn an unproofed firearm, with certain exceptions for military organisations. The proof process is that of testing a firearm for integrity using

2295-410: The unibody system (also referred to as unitary construction, unitary body–chassis or body–frame integral construction), in which the body of the vehicle, its floor pan, and chassis form a single structure, while the skin adds relatively little strength or stiffness. Some armoured fighting vehicles use a monocoque structure with a body shell built up from armour plates, rather than attaching them to

2346-528: The wooden hulls did, greatly improving performance. In the United States, Northrop was a major pioneer, introducing techniques used by his own company and Douglas with the Northrop Alpha . In motor racing, the safety of the driver depends on the car body, which must meet stringent regulations, and only a few cars have been built with monocoque structures. An aluminum alloy monocoque chassis

2397-472: Was first used in the 1962 Lotus 25 Formula 1 race car and McLaren was the first to use carbon-fiber-reinforced polymers to construct the monocoque of the 1981 McLaren MP4/1 . In 1990 the Jaguar XJR-15 became the first production car with a carbon-fiber monocoque. The term monocoque is frequently misapplied to unibody cars. Commercial car bodies are almost never true monocoques but instead use

2448-486: Was further developed in Germany by LFG Roland using the patented Wickelrumpf (wrapped hull) form later licensed by them to Pfalz Flugzeugwerke who used it on several fighter aircraft. Each half of the fuselage shell was formed over a male mold using two layers of plywood strips with fabric wrapping between them. The early plywood used was prone to damage from moisture and delamination. While all-metal aircraft such as

2499-426: Was produced in the 1950s using a monocoque hollow shell of sheet-steel pressings welded together, into which the engine and transmission were installed from underneath. The machine could be tipped onto its side, resting on the bolt-on footboards for mechanical access. A monocoque framed scooter was produced by Yamaha from 1960–1962. Model MF-1 was powered by a 50 cc engine with a three-speed transmission and

2550-436: Was very light since a major portion of its structural support was provided by its single-wall steel balloon fuel tanks , which hold their shape while under acceleration by internal pressure. Balloon tanks are not true monocoques but act in the same way as inflatable shells . A balloon tank skin only handles tensile forces while compression is resisted by internal liquid pressure in a way similar to semi-monocoques braced by

2601-509: Was won by Peter Williams on the monocoque-framed John Player Special that he helped to design based on Norton Commando . Honda also experimented with the NR500 , a monocoque Grand Prix racing motorcycle in 1979 . The bike had other innovative features, including an engine with oval shaped cylinders, and eventually succumbed to the problems associated with attempting to develop too many new technologies at once. In 1987 John Britten developed

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