1.
New Orleans
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New Orleans is a major United States port and the largest city and metropolitan area in the state of Louisiana. The population of the city was 343,829 as of the 2010 U. S. Census, the New Orleans metropolitan area had a population of 1,167,764 in 2010 and was the 46th largest in the United States. The New Orleans–Metairie–Bogalusa Combined Statistical Area, a trading area, had a 2010 population of 1,452,502. The city is named after the Duke of Orleans, who reigned as Regent for Louis XV from 1715 to 1723, as it was established by French colonists and it is well known for its distinct French and Spanish Creole architecture, as well as its cross-cultural and multilingual heritage. New Orleans is also famous for its cuisine, music, and its celebrations and festivals, most notably Mardi Gras. The city is referred to as the most unique in the United States. New Orleans is located in southeastern Louisiana, straddling the Mississippi River, the city and Orleans Parish are coterminous. The city and parish are bounded by the parishes of St. Tammany to the north, St. Bernard to the east, Plaquemines to the south, and Jefferson to the south and west. Lake Pontchartrain, part of which is included in the city limits, lies to the north, before Hurricane Katrina, Orleans Parish was the most populous parish in Louisiana. As of 2015, it ranks third in population, trailing neighboring Jefferson Parish, La Nouvelle-Orléans was founded May 7,1718, by the French Mississippi Company, under the direction of Jean-Baptiste Le Moyne de Bienville, on land inhabited by the Chitimacha. It was named for Philippe II, Duke of Orléans, who was Regent of the Kingdom of France at the time and his title came from the French city of Orléans. The French colony was ceded to the Spanish Empire in the Treaty of Paris, during the American Revolutionary War, New Orleans was an important port for smuggling aid to the rebels, transporting military equipment and supplies up the Mississippi River. Bernardo de Gálvez y Madrid, Count of Gálvez successfully launched a campaign against the British from the city in 1779. New Orleans remained under Spanish control until 1803, when it reverted briefly to French oversight, nearly all of the surviving 18th-century architecture of the Vieux Carré dates from the Spanish period, the most notable exception being the Old Ursuline Convent. Napoleon sold Louisiana to the United States in the Louisiana Purchase in 1803, thereafter, the city grew rapidly with influxes of Americans, French, Creoles, and Africans. Later immigrants were Irish, Germans, and Italians, Major commodity crops of sugar and cotton were cultivated with slave labor on large plantations outside the city. The Haitian Revolution ended in 1804 and established the republic in the Western Hemisphere. It had occurred several years in what was then the French colony of Saint-Domingue
2.
Museum ship
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A museum ship, also called a memorial ship, is a ship that has been preserved and converted into a museum open to the public for educational or memorial purposes. Some are also used for training and recruitment purposes, mostly for the number of museum ships that are still operational. Many, if not most, museum ships are also associated with a maritime museum, only a few survive, sometimes because of historical significance, but more often due to luck and circumstance. The restoration and maintenance of museum ships presents problems for historians who are asked for advice, for instance, the rigging of sailing ships has almost never survived, and so the rigging plan must be reconstructed from various sources. Studying the ships also allows historians to analyze how life on and operation of the ships took place, numerous scientific papers have been written on ship restoration and maintenance, and international conferences are held discussing the latest developments. Another consideration is the distinction between a museum ship, and a ship replica. As repairs accumulate over time, less and less of the ship is of the materials. Visitors without historical background are often unable to distinguish between a historical museum ship and a ship replica, which may serve solely as a tourist attraction. Typically the visitor enters via gangplank, wanders around on the deck, then goes below, usually using the original stairways, giving a sense of how the crew got around. The interior features restored but inactivated equipment, enhanced with mementos including old photographs, explanatory displays, pages from the logs, menus. Some add recorded sound effects, audio tours or video displays to enhance the experience, in some cases, the ships radio room has been brought back into use, with volunteers operating amateur radio equipment. Often, the callsign assigned is a variation on the identification of the ship. For example, the submarine USS Cobia, which had the call NBQV, is now on the air as NB9QV. The World War II submarine USS Pampanito, berthed at the San Francisco Maritime National Historical Park, had the wartime call NJVT and is now on the air as NJ6VT, in other cases, such as the USS Missouri, a distinctive call is used. This radio work not only helps restore part of the vessel, a number of the larger museum ships have begun to offer hosting for weddings, meetings, other events, and sleepovers, and on a few ships still seaworthy, cruises. In the United States, this includes the USS Constitutions annual turnaround, a place on the deck is by invitation or lottery only, and highly prized. Many consider the appeal of an interesting old vessel on the city waterfront strong enough that any port city should showcase one or more museum ships. This may even include building a ship at great expense
3.
PT boat
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A PT boat was a torpedo-armed fast attack craft used by the United States Navy in World War II. The PT boat was very different from the first generation of torpedo boat and these first generation torpedo boats rode low in the water, displaced up to 300 tons, and had a top speed of 25 to 27 kn. During World War I the US and UK developed the first high-performance motor torpedo boats and corresponding torpedo tactics, but these projects were all quickly disbanded with the Armistice. World War II PT boats continued to some of the advances in planing hull design borrowed from offshore powerboat racing and were able to grow in size due to advancements in engine technology. During World War II, PT boats engaged enemy warships, transports, tankers, barges, as gunboats they could be effective against enemy small craft, especially armored barges used by the Japanese for inter-island transport. Several saw service with the Philippine Navy, where they were named Q-boats most probably after President Manuel L. Quezon Primary anti-ship armament was four 2,600 pound Mark 8 torpedoes. Launched by 21-inch Mark 18 torpedo tubes, each bore a 466-pound TNT warhead and had a range of 16,000 yards at 36 knots, Two twin M2.50 cal machine guns were mounted for anti-aircraft defense and general fire support. Some boats shipped a 20 mm Oerlikon cannon, propulsion was via a trio of Packard 4M-2500 and later 5M-2500 supercharged gasoline-fueled, liquid-cooled marine engines. In September 1914, Hickman completed plans for a 50-foot Sea Sled torpedo boat and his plan was promptly rejected by the Admiralty, so Hickman built and launched his own privately financed 41-foot Sea Sled capable of carrying a single 18 Whitehead Mark 5 torpedo. In February 1915, this Hickman sea sled demonstrated 35 kn speeds in rough seas off Boston to both US and foreign representatives but again, he received no contracts. The Admiralty representative for this sea sled demonstration was Lieutenant G. C. E, in the summer of 1915, Lieutenants Hampden, Bremner, and Anson approached John I. Thornycroft & Company about developing a high speed torpedo boat. Meanwhile, in August 1915, the General Board of the United States Navy approved the purchase of an experimental small torpedo boat that could be transportable. This contract for C-250 ended up going to Greenport Basin and Construction Company, of Greenport, NY. When it eventually was delivered and tested in the Summer of 1917, it was not deemed a success, so a second boat of the sea sled design was ordered from Hickman in either late 1917 or early 1918. Using his previous design from September 1914 and the unsuccessful bid for C-250. The Sea Sled would not surface again as a torpedo boat topic until 1939, in 1922, the US Navy reconsidered using small internal combustion engine powered torpedo boats. As a result, two types of British Royal Navy Coastal Motor Boats were obtained for testing, the larger boat was used for experiments until 1930
4.
Packard
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Packard was an American luxury automobile marque built by the Packard Motor Car Company of Detroit, Michigan, United States, and later by the Studebaker-Packard Corporation of South Bend, Indiana. The first Packard automobiles were produced in 1899, and the last in 1958, with one of the last concept cars built in 1956, henry Bourne Joy, a member of one of Detroits oldest and wealthiest families, bought a Packard. Impressed by its reliability, he visited the Packards and soon enlisted a group of investors—including Truman Handy Newberry, on October 2,1902, this group refinanced and renamed the New York and Ohio Automobile Company as the Packard Motor Car Company, with James Packard as president. Alger later served as vice president, Packard moved operations to Detroit soon after, and Joy became general manager. An original Packard, reputedly the first manufactured, was donated by a grateful James Packard to his alma mater, Lehigh University, another is on display at the Packard Museum in Warren, Ohio. In the beginning, all Packards had a single-cylinder engine until 1903, Packard produced its Twin Six model series of 12-cylinder cars from 1915 to 1923. The marque developed a following among wealthy purchasers both in the United States and abroad, competing with European marques like Rolls-Royce and Mercedes Benz, the 3,500, 000-square-foot Packard plant on East Grand Boulevard in Detroit was located on over 40 acres of land. Its skilled craftsmen practiced over 80 trades, the dilapidated plant still stands, despite repeated fires. The factory is in proximity to the current General Motors Detroit/Hamtramck Assembly. Architect Kahn also designed the Packard Proving Grounds at Utica, Michigan, from this beginning, through and beyond the 1930s, Packard-built vehicles were perceived as highly competitive among high-priced luxury American automobiles. The company was referred to as being one of the Three Ps of American motordom royalty, along with Pierce-Arrow of Buffalo, New York and Peerless of Cleveland. For most of its history, Packard was guided by its President and General Manager James Alvan Macauley, inducted into the Automobile Hall of Fame, Macauley made Packard the number one designer and producer of luxury automobiles in the United States. The marque was also highly competitive abroad, with markets in 61 countries, gross income for the company was $21,889,000 in 1928. Macauley was also responsible for the iconic Packard slogan, Ask the Man Who Owns One, in the 1920s, Packard exported more cars than any other in its price class, and in 1930, sold almost twice as many abroad as any other marque priced over $2000. In 1931,10 Packards were owned by Japans royal family, between 1924 and 1930, Packard was also the top-selling luxury brand. In addition to excellent luxury cars, Packard built trucks, a Packard truck carrying a three-ton load drove from New York City to San Francisco between 8 July and 24 August 1912. The same year, Packard had service depots in 104 cities, the Packard Motor Corporation Building at Philadelphia, also designed by Albert Kahn, was built in 1910-1911. It was added to the National Register of Historic Places in 1980, by 1931, Packards were also being produced in Canada
5.
V12 engine
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By using split crankpins or ignoring minor vibrations, any V angle is possible. The 180° configuration is referred to as a flat-twelve engine or a boxer although it is in reality a 180° V since the pistons can. This is not important in a car if all-out performance is the only goal. Since cost and fuel economy are usually important even in luxury and racing cars and it is often used in marine engines where great power is required, and the hull width is limited, but a longer vessel allows faster hull speed. In twin-propeller boats, two V12 engines can be enough to sit side-by-side, while three V12 engines are sometimes used in high-speed three-propeller configurations. Large, fast cruise ships can have six or more V12 engines, after World War II, the compact, more powerful, and vibration-free turboprop and turbojet engines replaced the V12 in aircraft applications. The first V-type engine was built in 1889 by Daimler, to a design by Wilhelm Maybach, by 1903 V8 engines were being produced for motor boat racing by the Société Antoinette to designs by Léon Levavasseur, building on experience gained with in-line four-cylinder engines. In 1904, the Putney Motor Works completed a new V12 marine racing engine—the first V12 engine produced for any purpose, a single camshaft mounted in the central V operated the valves directly. As in many engines, the camshaft could be slid longitudinally to engage a second set of cams. Starting is by pumping a charge into each cylinder and switching on the trembler coils, a sliding camshaft gave direct reversing. The camshaft has fluted webs and main bearings in graduated thickness from the largest at the flywheel end, displacing 1,120 cu in, the engine weighed 950 pounds and developed 150 bhp. Little is known of the achievements in the 40-foot hull for which it was intended. One V12 Dörwald marine engine was still running in a Hong Kong junk in the late-1960s. Two more V12s appeared in the 1909-1910 motor boat racing season, the Lamb Boat & Engine Company of Clinton, Iowa built a 1,559 cu in engine for the companys 32-foot Lamb IV. It weighed in at 2,114 pounds, no weight is known for the massive 3,464 cu in F-head engine built by the Orleans Motor Company. Output is quoted as nearly 400 bhp, by 1914, when Panhard built two 2,356 cu in engines with four-valve cylinder heads the V12 was well established in motor boat racing. In October 1913, Louis Coatalen, chief engineer of the Sunbeam Motor Car Company entered a V12 powered car in the Brooklands short, the engine displaced 9 L, with bore and stroke of 80 x 150 mm. An aluminum crankcase carried two blocks of three cylinders each along each side, with a 60 degree included angle, the cylinders were of iron, with integral cylinder heads with L-shaped combustion chambers
6.
Identification friend or foe
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Identification, friend or foe is an identification system designed for command and control. It enables military and national interrogation systems to identify aircraft, vehicles or forces as friendly and to determine their bearing, IFF may be used by both military and civilian aircraft. IFF was first developed during the Second World War, with the arrival of radar, despite the name, IFF can only positively identify friendly targets, not hostile ones. If an IFF interrogation receives no reply or a reply, the object cannot be identified as friendly. There are in addition many reasons that friendly aircraft may not properly reply to IFF, the broadest characterization is that of friend, enemy, neutral, or unknown. CID not only can reduce friendly fire incidents, but also contributes to overall tactical decision-making and this led to incidents such as the battle of Barking Creek, over Britain, and the air attack on the fortress of Koepenick, over Germany. Already before the deployment of their Chain Home radar system, the RAF had considered the problem of IFF, robert Watson-Watt had filed patents on such systems in 1935 and 1936 respectively. By 1938, researchers at Bawdsey Manor began experiments with reflectors consisting of a dipole antennas tuned to resonate at the frequency of the CH radars. When a pulse from the CH transmitter hit the aircraft, the antennas would resonate for a short time, the antenna was connected to a motorized switch that periodically shorted it out, preventing it from producing a signal. This caused the return on the CH set to periodically lengthen and shorten as the antenna was turned on and off. It was suspected this system would be of use in practice. This consisted of a set of tracking stations using HF/DF radio direction finders and their aircraft radios were modified to send out a 1 kHz tone for 14 seconds every minute, allowing the tracking stations ample time to measure the aircrafts bearing. Known as pip-squeak, the system worked but was labour-intensive and did not display its information directly to the radar operators, a system that worked directly with the radar was clearly desirable. The first active IFF transponder was the IFF Mark I and was put into operation in 1939, on receipt of a signal from the CH radar, an oscillator in the system began to ring with the same frequency. This signal was amplified and sent out an omnidirectional monopole antenna, the oscillator circuit rang only for a short time, causing the signal to quickly disappear again. Since the signal was received at the time as the original reflection of the CH signal. Mark I was technically complete as the war began, but a lack of sets meant it was not available in quantity, pip-squeak was kept in operation during this period, but as the Battle ended, IFF Mark I was quickly put into operation. Pip-squeak was still used for areas over land where CH did not cover, the primary problem with the Mark I was that it operated at a single set frequency
7.
Bofors 40 mm gun
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The Bofors 40 mm gun, often referred to simply as the Bofors gun, is an anti-aircraft/multi-purpose autocannon designed in the 1930s by the Swedish arms manufacturer AB Bofors. It was one of the most popular medium-weight anti-aircraft systems during World War II, a small number of these weapons remain in service to this day, and saw action as late as the Gulf War. In the post-war era the original design was not suitable for action against jet powered aircraft, so Bofors introduced a new model of more power. In spite of sharing almost nothing with the design other than the calibre and the distinctive conical flash hider. Although not as popular as the original L/60 model, the L/70 remains in service to this day, especially as a weapon for light armored vehicles. Bofors itself has been part of BAE Systems AB since March 2005, the Swedish Navy purchased a number of 2 pounder Pom-Poms from Vickers as anti-aircraft guns in 1922. The Navy approached Bofors about the development of a capable replacement. Bofors signed a contract in late 1928, Bofors produced a gun that was a smaller version of a 57 mm semi-automatic gun developed as an anti-torpedo boat weapon in the late 19th century by Finspong. Their first test gun was a re-barreled Nordenfelt version of the Finspong gun, testing of this gun in 1929 demonstrated that a problem existed feeding the weapon in order to maintain a reasonable rate of fire. A mechanism that was enough to handle the stresses of moving the large round was too heavy to move quickly enough to fire rapidly. One attempt to solve this problem used zinc shell cases that burned up when fired and this proved to leave heavy zinc deposits in the barrel, and had to be abandoned. This seemed to be the solution they needed, improving firing rates to a level. During this period Krupp purchased a share of Bofors. Krupp engineers started the process of updating the Bofors factories to use equipment and metallurgy. The prototype was completed and fired in November 1931, and by the middle of the month it was firing strings of two and three rounds. Changes to the mechanism were all that remained, and by the end of the year it was operating at 130 rounds per minute. Continued development was needed to turn it into a suitable for production. Since acceptance trials had been passed the year before, this known as the 40 mm akan M/32
8.
Autocannon
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An autocannon or automatic cannon is a large, fully automatic, rapid-fire projectile weapon that fires armour-piercing or explosive shells, as opposed to the bullet fired by a machine gun. Autocannons often have a larger calibre than a gun, but are usually smaller than a field gun or other artillery. When used on its own, the word autocannon indicates a single-barrel weapon, when multiple rotating barrels are involved, the word rotary is added, and such a weapon is referred to as a rotary autocannon. As such, ammunition is fed from a belt to reduce reloading or for a faster rate of fire. They can use a variety of ammunition, common shells include high-explosive dual-purpose types, any variety of armour-piercing types, both the US25 mm Bushmaster and the British 30 mm Rarden have relatively slow rates of fire so as not to use ammunition too quickly. The rate of fire of a modern autocannon ranges from 90 rounds per minute, systems with multiple barrels can have rates of fire of over 10,000 rounds per minute. The first modern autocannon was the British QF1 pounder, also known as the pom-pom, during the First World War, autocannons were mostly used in the trenches as an anti-aircraft gun. Attempts to use them in aircraft failed as the severely limited both speed and altitude, thus making successful interception impossible. The more effective QF2 pounder naval gun would be developed during the war to serve as an anti-aircraft, autocannons would serve in a much greater capacity during the Second World War. During the inter-war years, aircraft underwent an evolution and the monoplane, pioneered as far back as the end of 1915, almost replaced wood. The subsequent increase in speed and durability greatly reduced the window of opportunity for defence and this was only reversed with the introduction of computer-controlled systems. The German Panzer II light tank, which was one of the most numerous in German service during the invasion of Poland and the campaign in France, used a 20 mm autocannon as its main armament. Although ineffective against tank armour even during the years of the war. Larger examples, such as the 40 mm Vickers S, were mounted in ground attack aircraft to serve as an anti-tank weapon, Polish 20 mm 38 Fk auto cannon was expensive to produce, but an exception. Unlike the Oerlikon, it was effective against all the tanks fielded in 1939, largely because it was built as an upgrade to the Oerlikon, Hispano—Suiza and it, with great difficulty, proved capable of knocking out even early Panzer IIIs and IVs. Only 55 were produced by the time of the Polish Defensive War, in aircraft, several factors brought about the replacement of rifle-calibre machine guns by autocannons. Early autocannons were heavy and had a rate of fire. Along with the speed, the size of aircraft grew substantially, particularly in the 1930s, so that the weight was less of an issue while the rate of fire, and reliability were greatly improved
9.
M4 cannon
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The 37 mm Automatic Gun, M4, known as the T9 during development, was a 37 mm recoil-operated autocannon designed by Browning Arms Company. The weapon, which was built by Colt, entered service in 1942 and it was used in the Bell P-39 Airacobra and P-63 Kingcobra. Designed primarily as a weapon, the gun had a muzzle velocity of 2,000 ft/s. It was normally loaded with shells, but could also be loaded with the M80 armor-piercing shell. It was magazine-fed and could be fired manually or by remote control through a solenoid mounted on the rear of the gun. The recoiling mechanism of the gun included the tube and tube extension, recuperator piston and piston rod, lock frame assembly, driving spring assemblies, and the breechblock assembly. The nonrecoiling parts included the block group, the feed box and feeding mechanism, the recuperator cylinder and bushing, the back plate group. As the gun was designed, ammunition could be fed by a 5-round clip. The 30-round endless belt version was used exclusively in production, the M4 gun fed only from the left. The 30-round endless belt magazine was given the designation M6, it had an oval-shaped framework providing a track for the endless belt, initial loading and cocking of the gun were accomplished manually. A safety feature incorporated in the design of the trigger mechanism prevented firing the round until the assembly was in the battery position. The breech was locked and unlocked by recoil action which brings the operating level guide pins against cams to raise, the function of the breechblock was to assist in the final chambering of the round, close the breech, and actuate the trigger trip. It also provided a mounting for the firing pin, the lock frame was retracted by recoil action during automatic firing and is forced forward by the driving springs. The back plate assembly, by absorbing the energy of the lock frame, the driving spring assemblies held the lock frame against the carrier dog until the carrier was released by carrier catch which was pivoted by the incoming round. The springs then drove the frame assembly forward to operate the ejector, chamber the round. Extraction, ejection, feeding and loading were accomplished during counter-recoil, if the trigger was held in the firing position, the gun would continue to fire automatically until the magazine was empty. The 37 mm cannon was disliked by pilots for its drooping trajectory, the only standard aircraft armed with the M4 to see service were the Bell P-39 Airacobra and the derivative P-63 Kingcobra. It was used as a standard aircraft in North Africa
10.
Oerlikon 20 mm cannon
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The Oerlikon 20 mm cannon is a series of autocannons, based on an original German 20 mm Becker design that appeared very early in World War I. It was widely produced by Oerlikon Contraves and others, with various models employed by both Allied and Axis forces during World War II, and many still in use today. During World War I, the German Reinhold Becker developed a 20 mm caliber cannon and this used a 20x70 RB cartridge and had a cyclic rate of fire of 300 rpm. It was used on a scale as an aircraft gun on Luftstreitkräfte warplanes. Because the Treaty of Versailles banned further production of weapons in Germany. SEMAG continued development of the weapon, and in 1924 had produced the SEMAG L, the Oerlikon firm, named after the Zürich suburb where it was based, then acquired all rights to the weapon, plus the manufacturing equipment and the employees of SEMAG. In 1927 the Oerlikon S was added to the product line. This fired a larger cartridge to achieve a muzzle velocity of 830 m/s, at the cost of increased weight. The purpose of development was to improve the performance of the gun as an anti-tank and anti-aircraft weapon. An improved version known as the 1S followed in 1930, three sizes of gun with their different ammunition and barrel length, but very similar mechanisms, continued to be developed in parallel. In 1930 Oerlikon reconsidered the application of its gun in aircraft and introduced the AF and AL, designed to be used in flexible mounts, the 15-round box magazine used by earlier versions of the gun was replaced by drum magazine holding 15 or 30 rounds. In 1935 it made an important step by introducing a series of guns designed to be mounted in or on the wings of fighter aircraft, designated with FF for Flügelfest meaning wing-mounted, these weapons were again available in the three sizes, with designations FF, FFL and FFS. The FF fired a larger cartridge than the AF, 20x72RB. The FF weighed 24 kg and achieved a velocity of 550 to 600 m/s with a rate of fire of 520 rpm. The FFL of 30 kg fired a projectile at a velocity of 675 m/s with a rate of fire of 500 rpm. And the FFS, which weighed 39 kg, delivered a high velocity of 830 m/s at a rate of fire of 470 rpm. Apart from changes to the design of the guns for wing-mounting and remote control, for the FF series drum sizes of 45,60,75 and 100 rounds were available, but most users chose the 60-round drum. The 1930s were a period of global re-armament, and a number of foreign firms took licenses for the Oerlikon family of aircraft cannon
11.
M2 Browning
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The M2 Machine Gun or Browning.50 Caliber Machine Gun is a heavy machine gun designed toward the end of World War I by John Browning. Its design is similar to Brownings earlier M1919 Browning machine gun, the M2 uses the much larger and much more powerful.50 BMG cartridge, which was developed alongside and takes its name from the gun itself. It has been referred to as Ma Deuce, in reference to its M2 nomenclature, the design has had many specific designations, the official designation for the current infantry type is Browning Machine Gun, Cal.50, M2, HB, Flexible. It is effective against infantry, unarmored or lightly armored vehicles and boats, light fortifications, the M2 has been produced longer than any other machine gun. The Browning.50 caliber machine gun has been used extensively as a vehicle weapon and it was heavily used during World War II, the Korean War, the Vietnam War, the Falklands War, the Iraq War and the War in Afghanistan in the 2000s and 2010s. It is the heavy machine gun of NATO countries, and has been used by many other countries as well. The M2 has been in use longer than any firearm in U. S. inventory except the.45 ACP M1911 pistol. The current M2HB is manufactured in the U. S. by General Dynamics, Ordnance for use by the U. S. government, and for allies via Foreign Military Sales, as well as foreign manufacturers such as FN Herstal. Machine guns were used in World War I, and weapons of larger than rifle caliber were appearing. Both the British and French had large caliber machine guns, the larger rounds were needed to defeat the armor that was being introduced to the battlefield. Armor was also appearing in the skies, during World War I, the Germans introduced a heavily armored airplane, the Junkers J. I. The armor made aircraft machine guns using conventional rifle ammunition ineffective, consequently, the American Expeditionary Forces commander General John J. Pershing asked for a larger caliber machine gun. Pershing asked the Army Ordnance Department to develop a gun with a caliber of at least 0.50 inches. U. S. Col. John Henry Parker, commanding a machine gun school in France, the Army Ordnance Department ordered eight experimental Colt machine guns rechambered for the French 11 mm cartridge. The French had developed a machine gun for an even larger caliber. The French 11 mm round was found to be unsuitable because its velocity was too low, Pershing wanted a bullet of at least 670 gr and a muzzle velocity of 2,700 ft/s. Development with the French round was dropped, around July 1917, John M. Browning started redesigning his.30 caliber machine gun for a larger caliber. Winchester worked on the cartridge, which was a version of the. 30-06
12.
Machine gun
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A machine gun is a fully automatic mounted or portable firearm designed to fire bullets in quick succession from an ammunition belt or magazine, typically at a rate of 300 to 1800 rounds per minute. Note that not all fully automatic firearms are machine guns, submachine guns, rifles, assault rifles, shotguns, pistols or cannons may be capable of fully automatic fire, but are not designed for sustained fire. Many machine guns also use belt feeding and open bolt operation, unlike semi-automatic firearms, which require one trigger pull per round fired, a machine gun is designed to fire for as long as the trigger is held down. Nowadays the term is restricted to heavy weapons, able to provide continuous or frequent bursts of automatic fire for as long as ammunition lasts. Machine guns are used against personnel, aircraft and light vehicles, or to provide suppressive fire. Some machine guns have in practice sustained fire almost continuously for hours, because they become very hot, practically all machine guns fire from an open bolt, to permit air cooling from the breech between bursts. They also usually have either a barrel cooling system, slow-heating heavyweight barrel, although subdivided into light, medium, heavy or general-purpose, even the lightest machine guns tend to be substantially larger and heavier than standard infantry arms. Medium and heavy guns are either mounted on a tripod or on a vehicle, when carried on foot. Medium machine guns use full-sized rifle rounds and are designed to be used from fixed positions mounted on a tripod. 50in, the M249 automatic rifle is operated by an automatic rifleman, but its ammunition may be carried by other Soldiers within the squad or unit. The M249 machine gun is a crew-served weapon, Machine guns usually have simple iron sights, though the use of optics is becoming more common. Many heavy machine guns, such as the Browning M2.50 caliber machine gun, are enough to engage targets at great distances. During the Vietnam War, Carlos Hathcock set the record for a shot at 7382 ft with a.50 caliber heavy machine gun he had equipped with a telescopic sight. This led to the introduction of.50 caliber anti-materiel sniper rifles, selective fire rifles firing a full-power rifle cartridge from a closed bolt are called automatic rifles or battle rifles, while rifles that fire an intermediate cartridge are called assault rifles. Unlocking and removing the spent case from the chamber and ejecting it out of the weapon as bolt is moving rearward Loading the next round into the firing chamber. Usually the recoil spring tension pushes bolt back into battery and a cam strips the new round from a feeding device, cycle is repeated as long as the trigger is activated by operator. Releasing the trigger resets the trigger mechanism by engaging a sear so the weapon stops firing with bolt carrier fully at the rear, the operation is basically the same for all autoloading firearms, regardless of the means of activating these mechanisms. Most modern machine guns use gas-operated reloading, a recoil actuated machine gun uses the recoil to first unlock and then operate the action. Machine guns such as the M2 Browning and MG42, are of this type, a cam, lever or actuator demultiplicates the energy of the recoil to operate the bolt
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