112-512: Surface targets: 4,000 meters The BK 27 (also BK27 or BK-27 ) (German abbreviation for Bordkanone , "on-board cannon") is a 27 mm (1.063 in) caliber revolver cannon manufactured by Mauser (now part of Rheinmetall ) of Germany. It was developed in the late 1960s for the MRCA (Multi Role Combat Aircraft) program that ultimately became the Panavia Tornado . The BK 27 is
224-568: A gas-operated cannon firing a series of 27×145 mm cartridges with a typical projectile weight of 260 g (9.2 oz), and a total weight for the complete round of 516 g (1.14 lb). Most models use a linked feed system for the ammunition; however, the Eurofighter Typhoon makes use of a specially developed variant of the BK 27 that uses a linkless feed system instead, which is intended to improve reliability. The Mauser BK 27
336-577: A lower house based on population; and the Senate , an upper house based on equal representation for each state. Federalism provides substantial autonomy to the 50 states, while the country's political culture promotes liberty , equality , individualism , personal autonomy , and limited government . One of the world's most developed countries , the United States has had the largest nominal GDP since about 1890 and accounted for over 15% of
448-503: A rifled barrel, the distance is measured between opposing lands or between opposing grooves ; groove measurements are common in cartridge designations originating in the United States , while land measurements are more common elsewhere in the world. Measurements "across the grooves" are used for maximum precision because rifling and the specific caliber so measured is the result of final machining process which cuts grooves into
560-692: A " 30 caliber rifle", which could accommodate any of a wide range of cartridges using a roughly 0.30 inches (7.6 mm) projectile; or as a "22 rimfire", referring to any rimfire firearms firing cartridges with a 22 caliber projectile. However, there can be significant differences in nominal bullet and bore dimensions, and all cartridges so "categorized" are not automatically identical in actual caliber. For example, 303 British firearms and projectiles are often "categorized" as ".30-caliber" alongside several dozen U.S. "30-caliber" cartridges despite using bullets of .310–.312-inch (7.87–7.92 mm) diameter while all U.S. "30-caliber" centerfire rifle cartridges use
672-580: A " Special Relationship " with the United Kingdom and strong ties with Canada , Australia , New Zealand , the Philippines , Japan , South Korea , Israel , and several European Union countries ( France , Italy , Germany , Spain , and Poland ). The U.S. works closely with its NATO allies on military and national security issues, and with countries in the Americas through
784-405: A .250 inch land diameter and .257 inch groove diameter. The .308 Winchester is measured across the grooves and uses a .308-in diameter (7.82-mm) bullet; the military-specification version is known as 7.62 × 51 mm NATO , so called because the bore diameter measured between the lands is 7.62 mm, and the cartridge has a case 51 mm long. Converting a rifle to fire a different cartridge in
896-455: A US " 45 caliber " firearm has a barrel diameter of roughly 0.45 inches (11.43mm). Barrel diameters can also be expressed using metric dimensions. For example, a "9 mm pistol" has a barrel diameter of about 9 millimeters. Since metric and US customary units do not convert evenly at this scale, metric conversions of caliber measured in decimal inches are typically approximations of the precise specifications in non-metric units, and vice versa. In
1008-412: A common, standard .308-inch (7.82 mm) bullet outside diameter. Using bullets larger than design specifications causes excessive pressures, while undersize bullets cause low pressures, insufficient muzzle velocities and fouling that will eventually lead to excessive pressures. Makers of early cartridge arms had to invent methods of naming cartridges since no established convention existed then. One of
1120-542: A coordinated, continent-wide military effort. Finally, deteriorating relations between the British military establishment and the colonists, relations that were already less than positive, set the stage for further distrust and dislike of British troops. Following their victory in the French and Indian War, Britain began to assert greater control over local colonial affairs, resulting in colonial political resistance ; one of
1232-534: A decentralized government that operated until 1789. After the British surrender at the siege of Yorktown in 1781 American sovereignty was internationally recognized by the Treaty of Paris (1783), through which the U.S. gained territory stretching west to the Mississippi River, north to present-day Canada, and south to Spanish Florida . The Northwest Ordinance (1787) established the precedent by which
SECTION 10
#17327806215741344-578: A decision was made to install an internal gun, this led to "manufacturing issues". Sutton claimed that during his strafing run the gun jammed after "twenty-six rounds", the HUD showing "GUN FAIL". During the debrief this problem was well known to both the pilots and ground crews. One pilot told Sutton: "They said that issue had been fixed", to which Sutton replied "Exactly. We've been here before." Data from Jane's Information Group Caliber In guns , particularly firearms , but not artillery, where
1456-470: A different definition may apply , caliber (or calibre ; sometimes abbreviated as " cal ") is the specified nominal internal diameter of the gun barrel bore – regardless of how or where the bore is measured and whether the finished bore matches that specification. It is measured in inches or in millimeters . In the United States it is expressed in hundredths of an inch; in the United Kingdom in thousandths; and elsewhere in millimeters. For example,
1568-432: A distance of 26 mi (42 km). Smoothbore cannon and carronade bores are designated by the weight in imperial pounds of spherical solid iron shot of diameter to fit the bore. Standard sizes are 6, 12, 18, 24, 32, and 42 pounds, with some non-standard weights using the same scheme. See Carronade#Ordnance . From about the mid-17th until the mid-19th century, the measurement of the bore of large gunpowder weapons
1680-407: A few prominent industrialists , largely by their formation of trusts and monopolies to prevent competition. Tycoons led the nation's expansion in the railroad , petroleum , and steel industries. The United States emerged as a pioneer of the automotive industry . These changes were accompanied by significant increases in economic inequality , slum conditions , and social unrest , creating
1792-638: A founding member of the World Bank , Organization of American States , NATO , and the United Nations , as well as a permanent member of the UN Security Council . The first documented use of the phrase "United States of America" is a letter from January 2, 1776. Stephen Moylan , a Continental Army aide to General George Washington , wrote to Joseph Reed , Washington's aide-de-camp , seeking to go "with full and ample powers from
1904-598: A multiple of the bore diameter. For example, a 4-inch gun of 50 calibers would have a barrel 4 in × 50 = 200 in long (written as 4" L/50 or 4"/50). A 16-inch gun of 50 calibers (16" L/50) has a barrel length of 50 × 16 = 800 inches (66 ft 8 in). Both 14-in and 16-in navy guns were common in World War II. The British Royal Navy insisted on 50-cal guns on ships as it would allow 1,900 to 2,700 lb (860 to 1,220 kg) shells to travel at an initial velocity of up to 1,800 mph (2,897 km/h) to
2016-598: A period of heightened, overt racism following Reconstruction, a time often called the nadir of American race relations . A series of Supreme Court decisions, including Plessy v. Ferguson , emptied the Fourteenth and Fifteenth Amendments of their force, allowing Jim Crow laws in the South to remain unchecked, sundown towns in the Midwest, and segregation in communities across the country , which would be reinforced by
2128-486: A pound; therefore, its barrel is smaller than the 12-gauge. This metric is used in Russia as "caliber number": e.g., "shotgun of the 12 caliber." The 16th caliber is known as "lordly" ( Russian : барский ). While shotgun bores can be expressed in calibers (the .410 bore shotgun is measured as .410 in (10.4 mm) in diameter, unlike with rifles the actual bore diameter of a smoothbore shotgun varies significantly down
2240-488: A prominent leader in the early 1960s. The Great Society plan of President Lyndon Johnson 's administration resulted in groundbreaking and broad-reaching laws, policies and a constitutional amendment to counteract some of the worst effects of lingering institutional racism . The counterculture movement in the U.S. brought significant social changes, including the liberalization of attitudes toward recreational drug use and sexuality . It also encouraged open defiance of
2352-432: A related expression. The gauge of a shotgun refers to how many lead spheres, each with a diameter equal to that of the bore, that amounts to one pound (454 g (1.0 lb)) in weight. In the case of a 12-gauge (18.5 mm) shotgun, it would take 12 spheres the size of the shotgun's bore to equal a pound. A numerically larger gauge indicates a smaller barrel: a 20-gauge (15.6 mm) shotgun requires more spheres to equal
SECTION 20
#17327806215742464-526: A sense of manifest destiny . The Missouri Compromise attempted to balance the desire of northern states to prevent the expansion of slavery into new territories with that of southern states to extend it, admitting Missouri as a slave state and Maine as a free state. It further prohibited slavery in all other lands of the Louisiana Purchase north of the 36°30′ parallel . As Americans expanded further into land inhabited by Native Americans,
2576-614: A sense of American identity as well. Men who otherwise never left their own colony now traveled across the continent to fight alongside men from decidedly different backgrounds but who were no less "American". British officers trained American officers for battle, most notably George Washington ; these officers would lend their skills and expertise to the colonists' cause during the American Revolutionary War to come. In addition, colonial legislatures and officials found it necessary to cooperate intensively in pursuit of
2688-632: A status solidified after its involvement in World War I . After Japan 's attack on Pearl Harbor in December 1941, the U.S. entered World War II . Its aftermath left the U.S. and the Soviet Union as the world's two superpowers and led to the Cold War , during which both countries struggled for ideological dominance and international influence . Following the Soviet Union's collapse and
2800-401: A year). Juvenile correctional facilities are operated by local or state governments and serve as longer-term placements for any minor adjudicated as delinquent and ordered by a judge to be confined. As of January 2023, the United States has the sixth-highest per capita incarceration rate in the world—531 people per 100,000 inhabitants—and the largest prison and jail population in
2912-495: Is based. The following table lists some of the commonly used calibers where both metric and US customary units are used as equivalents. Due to variations in naming conventions, and the whims of the cartridge manufacturers, bullet diameters can vary widely from the diameter implied by the name. For example, a difference of 0.045 in (1.15 mm) occurs between the smallest and largest of the several cartridges designated as ".38 caliber". Shotguns are classed according to gauge,
3024-591: Is believed to be the first widespread culture in the Americas. Over time, indigenous North American cultures grew increasingly sophisticated, and some, such as the Mississippian culture , developed agriculture , architecture , and complex societies . In the post-archaic period , the Mississippian cultures were located in the midwestern , eastern , and southern regions, and the Algonquian in
3136-498: Is known as the presidential system , in contrast to the parliamentary system , where the executive is part of the legislative body. Many countries around the world imitated this aspect of the 1789 Constitution of the United States , especially in the Americas. The Constitution is silent on political parties. However, they developed independently in the 18th century with the Federalist and Anti-Federalist parties. Since then,
3248-419: Is much variance in the use of the term "small-bore", which over the years has changed considerably, with anything under 0.577 inches (14.7 mm) considered "small-bore" prior to the mid-19th century. While modern firearms are generally referred to by the name of the cartridge the gun is chambered for, they are still categorized together based on bore diameter. For example, a firearm might be described as
3360-438: Is now the United States experienced conflicts with Native Americans, they also engaged in trade, exchanging European tools for food and animal pelts. Relations ranged from close cooperation to warfare and massacres. The colonial authorities often pursued policies that forced Native Americans to adopt European lifestyles, including conversion to Christianity. Along the eastern seaboard, settlers trafficked African slaves through
3472-552: Is the federal agency charged with addressing most environmental-related issues . The idea of wilderness has shaped the management of public lands since 1964, with the Wilderness Act . The Endangered Species Act of 1973 provides a way to protect threatened and endangered species and their habitats. The United States Fish and Wildlife Service implements and enforces the Act. In 2024, the U.S. ranked 34th among 180 countries in
Mauser BK-27 - Misplaced Pages Continue
3584-751: Is used in the Panavia Tornado , the Alpha Jet , the JAS 39 Gripen , and the Eurofighter Typhoon . At one time Lockheed Martin was considering a licensed-built version for the F-35 Lightning II . Rheinmetall has also developed remote-controlled naval versions, the MN 27 GS and the MLG 27 fully automatic naval guns, which are installed on many ships of the German Navy . Ninety-nine MLG 27s have been ordered by
3696-603: The Allies of World War I , helping to turn the tide against the Central Powers . In 1920, a constitutional amendment granted nationwide women's suffrage . During the 1920s and '30s, radio for mass communication and the invention of early television transformed communications nationwide. The Wall Street Crash of 1929 triggered the Great Depression , which President Franklin D. Roosevelt responded to with
3808-553: The Atlantic slave trade . The original Thirteen Colonies that would later found the United States were administered as possessions of Great Britain , and had local governments with elections open to most white male property owners . The colonial population grew rapidly, eclipsing Native American populations; by the 1770s, the natural increase of the population was such that only a small minority of Americans had been born overseas. The colonies' distance from Britain allowed for
3920-549: The Environmental Performance Index . The country joined the Paris Agreement on climate change in 2016 and has many other environmental commitments. The United States is a federal republic of 50 states and a separate federal capital district, Washington, D.C. It also asserts sovereignty over five unincorporated territories and several uninhabited island possessions . The U.S. is
4032-500: The Federal Bureau of Investigation (FBI) and the U.S. Marshals Service have national jurisdiction and specialized duties, such as protecting civil rights , national security and enforcing U.S. federal courts ' rulings and federal laws. State courts conduct most civil and criminal trials, and federal courts handle designated crimes and appeals of state court decisions . There is no unified "criminal justice system" in
4144-720: The Great Lakes , Mississippi River and Gulf of Mexico . British colonization of the East Coast began with the Virginia Colony (1607) and Plymouth Colony (1620). The Mayflower Compact and the Fundamental Orders of Connecticut established precedents for representative self-governance and constitutionalism that would develop throughout the American colonies. While European settlers in what
4256-719: The Great Lakes region and along the Eastern Seaboard , while the Hohokam culture and Ancestral Puebloans inhabited the southwest . Native population estimates of what is now the United States before the arrival of European immigrants range from around 500,000 to nearly 10 million. Christopher Columbus began exploring the Caribbean for Spain in 1492, leading to Spanish-speaking settlements and missions from Puerto Rico and Florida to New Mexico and California . France established its own settlements along
4368-596: The Midwest . At the same time, about one million French Canadians migrated from Quebec to New England . During the Great Migration , millions of African Americans left the rural South for urban areas in the North. Alaska was purchased from Russia in 1867. The Compromise of 1877 effectively ended Reconstruction and white supremacists took local control of Southern politics . African Americans endured
4480-688: The National Park Service and other agencies. About 28% of the country's land is publicly owned and federally managed, primarily in the Western States . Most of this land is protected , though some is leased for commercial use, and less than one percent is used for military purposes. Environmental issues in the United States include debates on non-renewable resources and nuclear energy , air and water pollution , biodiversity , logging and deforestation , and climate change . The U.S. Environmental Protection Agency (EPA)
4592-596: The New Deal , a series of sweeping programs and public works projects combined with financial reforms and regulations . All were intended to protect against future economic depressions. Initially neutral during World War II , the U.S. began supplying war materiel to the Allies of World War II in March 1941 and entered the war in December after the Empire of Japan 's attack on Pearl Harbor . The U.S. developed
Mauser BK-27 - Misplaced Pages Continue
4704-778: The Organization of American States and the United States–Mexico–Canada Free Trade Agreement . In South America, Colombia is traditionally considered to be the closest ally of the United States. The U.S. exercises full international defense authority and responsibility for Micronesia , the Marshall Islands , and Palau through the Compact of Free Association . It has increasingly conducted strategic cooperation with India , but its ties with China have steadily deteriorated. Since 2014,
4816-648: The Pentium microprocessor in accordance with Moore's law , rechargeable lithium-ion batteries , the first gene therapy trial, and cloning either emerged in the U.S. or were improved upon there. The Human Genome Project was formally launched in 1990, while Nasdaq became the first stock market in the United States to trade online in 1998. In the Gulf War of 1991, an American-led international coalition of states expelled an Iraqi invasion force that had occupied neighboring Kuwait . The September 11 attacks on
4928-591: The Spanish–American War . (The Philippines was granted full independence from the U.S. on July 4, 1946, following World War II. Puerto Rico and Guam have remained U.S. territories.) American Samoa was acquired by the United States in 1900 after the Second Samoan Civil War . The U.S. Virgin Islands were purchased from Denmark in 1917. The United States entered World War I alongside
5040-623: The United States ( U.S. ) or America , is a country primarily located in North America . It is a federal union of 50 states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the states of Alaska to the northwest and the archipelagic Hawaii in the Pacific Ocean . The United States also asserts sovereignty over five major island territories and various uninhabited islands . The country has
5152-700: The cotton gin made the institution increasingly profitable for Southern elites . This sectional conflict regarding slavery culminated in the American Civil War (1861–1865). Eleven slave states seceded and formed the Confederate States of America , while the other states remained in the Union . War broke out in April 1861 after the Confederates bombarded Fort Sumter . After
5264-523: The end of the Cold War in 1991, the U.S. emerged as the world's sole superpower , wielding significant geopolitical influence globally . The U.S. national government is a presidential constitutional federal republic and liberal democracy with three separate branches : legislative , executive , and judicial . It has a bicameral national legislature composed of the House of Representatives ,
5376-537: The fall of communism and the collapse of the Soviet Union , which marked the end of the Cold War and left the United States as the world's sole superpower . The 1990s saw the longest recorded economic expansion in American history , a dramatic decline in U.S. crime rates , and advances in technology . Throughout this decade, technological innovations such as the World Wide Web , the evolution of
5488-400: The global economy in 2023. It possesses by far the largest amount of wealth of any country and has the highest disposable household income per capita among OECD countries. The U.S. ranks among the world's highest in economic competitiveness , productivity , innovation , human rights , and higher education . Its hard power and cultural influence have a global reach. The U.S. is
5600-813: The 1775 Battles of Lexington and Concord , igniting the American Revolutionary War . At the Second Continental Congress , the colonies appointed George Washington commander-in-chief of the Continental Army , and created a committee that named Thomas Jefferson to draft the Declaration of Independence . Two days after passing the Lee Resolution to create an independent nation the Declaration
5712-520: The 2010s, political polarization in the country increased between liberal and conservative factions. This polarization was capitalized upon in the January 2021 Capitol attack , when a mob of insurrectionists entered the U.S. Capitol and sought to prevent the peaceful transfer of power in an attempted self-coup d'état . The United States is the world's third-largest country by total area behind Russia and Canada. The 48 contiguous states and
SECTION 50
#17327806215745824-596: The American West have an alpine climate . The climate is arid in the Southwest, Mediterranean in coastal California , and oceanic in coastal Oregon , Washington , and southern Alaska . Most of Alaska is subarctic or polar . Hawaii , the southern tip of Florida and U.S. territories in the Caribbean and Pacific are tropical . States bordering the Gulf of Mexico are prone to hurricanes, and most of
5936-475: The Declaration of Independence on July 4, 1776. The term "United States" and the initialism "U.S.", used as nouns or as adjectives in English, are common short names for the country. The initialism "USA", a noun, is also common. "United States" and "U.S." are the established terms throughout the U.S. federal government , with prescribed rules. In English, the term "America" rarely refers to topics unrelated to
6048-573: The District of Columbia occupy a combined area of 3,119,885 square miles (8,080,470 km ). The coastal plain of the Atlantic seaboard gives way to inland forests and rolling hills in the Piedmont plateau region. The Appalachian Mountains and the Adirondack massif separate the East Coast from the Great Lakes and the grasslands of the Midwest . The Mississippi River System ,
6160-573: The Elder concluded that major military resources needed to be devoted to North America to win the war against France. For the first time, the continent became one of the main theaters of what could be termed a " world war ". The British colonies' position as an integral part of the British Empire became more apparent during the war, with British military and civilian officials becoming a more significant presence in American life. The war increased
6272-452: The German Navy so far. The cannon is a single-barrel, high-performance, breech-cylinder gun operated by a fully automatic, electrically fired, gas-operated system at a selective rate of 1000 or 1700 rounds per minute(+/− 100 rpm). The Mauser BK 27 utilizes pyrotechnic cocking charges to cycle the action. The gun mainly fires mine shells as these have the best effect against aircraft, there are also several types of armor piercing shells like
6384-465: The January 1863 Emancipation Proclamation , many freed slaves joined the Union army . The war began to turn in the Union's favor following the 1863 Siege of Vicksburg and Battle of Gettysburg , and the Confederacy surrendered in 1865 after the Union's victory in the Battle of Appomattox Court House . The Reconstruction era followed the war. After the assassination of President Abraham Lincoln , Reconstruction Amendments were passed to protect
6496-476: The Rocky Mountains, the Yellowstone Caldera , is the continent's largest volcanic feature. In 2021, the United States had 8% of global permanent meadows and pastures and 10% of cropland. With its large size and geographic variety, the United States includes most climate types. East of the 100th meridian , the climate ranges from humid continental in the north to humid subtropical in the south. The western Great Plains are semi-arid . Many mountainous areas of
6608-451: The U.S. has become a key ally of Ukraine ; it has also provided the country with significant military equipment and other support in response to Russia's 2022 invasion . The president is the commander-in-chief of the United States Armed Forces and appoints its leaders, the secretary of defense and the Joint Chiefs of Staff . The Department of Defense , which is headquartered at the Pentagon near Washington, D.C., administers five of
6720-661: The U.S. territories." Despite disparate systems of confinement, four main institutions dominate: federal prisons , state prisons , local jails, and juvenile correctional facilities . Federal prisons are run by the Federal Bureau of Prisons and hold people who have been convicted of federal crimes, including pretrial detainees. State prisons, run by the official department of correction of each state, hold sentenced people serving prison time (usually longer than one year) for felony offenses. Local jails are county or municipal facilities that incarcerate defendants prior to trial; they also hold those serving short sentences (typically under
6832-416: The United States and the peaceful transfer of power , respectively. The Louisiana Purchase of 1803 from France nearly doubled the territory of the United States. Lingering issues with Britain remained , leading to the War of 1812 , which was fought to a draw. Spain ceded Florida and its Gulf Coast territory in 1819. In the late 18th century, American settlers began to expand westward , many with
SECTION 60
#17327806215746944-541: The United States entered the Cold War, where geopolitical tensions between the U.S. and the Soviet Union led the two countries to dominate world affairs . The U.S. utilized the policy of containment to limit the USSR's sphere of influence, and prevailed in the Space Race , which culminated with the first crewed Moon landing in 1969. Domestically, the U.S. experienced economic growth , urbanization , and population growth following World War II . The civil rights movement emerged, with Martin Luther King Jr. becoming
7056-495: The United States has operated as a de facto two-party system , though the parties in that system have been different at different times. The two main national parties are presently the Democratic and the Republican . The former is perceived as relatively liberal in its political platform while the latter is perceived as relatively conservative . In the American federal system , sovereign powers are shared between two levels of elected government: national and state. People in
7168-402: The United States in 2001 by the pan-Islamist militant organization al-Qaeda led to the war on terror , and subsequent military interventions in Afghanistan and Iraq . The cultural impact of the attacks was profound and long-lasting. The U.S. housing bubble culminated in 2007 with the Great Recession , the largest economic contraction since the Great Depression. Coming to a head in
7280-415: The United States of America to Spain" to seek assistance in the Revolutionary War effort. The first known public usage is an anonymous essay published in the Williamsburg newspaper, The Virginia Gazette , on April 6, 1776. By June 1776, the "United States of America" appeared in the Articles of Confederation and the Declaration of Independence . The Second Continental Congress adopted
7392-434: The United States, despite the usage of "the Americas " as the totality of North and South America. "The States" is an established colloquial shortening of the name, used particularly from abroad; "stateside" is the corresponding adjective or adverb. The first inhabitants of North America migrated from Siberia across the Bering land bridge about 12,000 years ago; the Clovis culture , which appeared around 11,000 BC,
7504-478: The United States, except Iran , North Korea , and Bhutan . Though Taiwan does not have formal diplomatic relations with the U.S., it maintains close unofficial relations. The United States regularly supplies Taiwan with military equipment to deter potential Chinese aggression. Its geopolitical attention also turned to the Indo-Pacific when the United States joined the Quadrilateral Security Dialogue with Australia, India, and Japan. The United States has
7616-509: The United States. The American prison system is largely heterogenous, with thousands of relatively independent systems operating across federal, state, local, and tribal levels. In 2023, "these systems [held] almost 2 million people in 1,566 state prisons, 98 federal prisons, 3,116 local jails, 1,323 juvenile correctional facilities, 181 immigration detention facilities, and 80 Indian country jails, as well as in military prisons , civil commitment centers, state psychiatric hospitals, and prisons in
7728-422: The bore diameter and the length of the cartridge case; for example, the 6.5×55mm Swedish cartridge has a bore diameter of 6.5 mm and a case length of 55 mm. The means of measuring a rifled bore varies, and may refer to the diameter of the lands or the grooves of the rifling. For example, the 257 Roberts and 250 Savage both use a .257 inch projectile; both 250 Savage and 257 Roberts rifle bores have
7840-545: The bullet weight in grains was designated, such as 45-70-405. This scheme was far more popular and was carried over after the advent of early smokeless powder cartridges such as the 30-30 Winchester and 22 Long . Later developments used terms to indicate relative power, such as .44 Special and .44 Magnum . Variations on these methods persist today, with new cartridges such as the 204 Ruger and 17 HMR (Hornady Magnum Rimfire). Metric diameters for small arms refer to cartridge dimensions and are expressed with an "×" between
7952-404: The contemporary English ( avoirdupois ) pound massed of approximately 454 g (1.001 lb). Thus, a French 32-pounder at the Battle of Trafalgar threw a shot with 1.138 kg (2.51 lb) more mass than an English 32-pounder. Complicating matters further, muzzle-loaded weapons require a significant gap between the sides of the tube bore and the surface of the shot. This is necessary so
8064-457: The contiguous United States are in the State of California, about 84 miles (135 km) apart. At an elevation of 20,310 feet (6,190.5 m), Alaska's Denali is the highest peak in the country and continent. Active volcanoes are common throughout Alaska's Alexander and Aleutian Islands , and Hawaii consists of volcanic islands. The supervolcano underlying Yellowstone National Park in
8176-556: The country's GDP. The U.S. has 42% of the world's nuclear weapons —the second-largest share after Russia. The United States has the third-largest combined armed forces in the world, behind the Chinese People's Liberation Army and Indian Armed Forces . The military operates about 800 bases and facilities abroad, and maintains deployments greater than 100 active duty personnel in 25 foreign countries. State defense forces (SDFs) are military units that operate under
8288-469: The country's territory would expand with the admission of new states , rather than the expansion of existing states. The U.S. Constitution was drafted at the 1787 Constitutional Convention to overcome the limitations of the Articles. It went into effect in 1789, creating a federal republic governed by three separate branches that together ensured a system of checks and balances . George Washington
8400-713: The development of self-governance, and the First Great Awakening , a series of Christian revivals , fueled colonial interest in religious liberty . For a century, the American colonists had been providing their own troops and materiel in conflicts with indigenous peoples allied with Britain's colonial rivals , especially France, and the Americans had begun to develop a sense of self-defense and self-reliance separate from Britain. The French and Indian War (1754–1763) took on new significance for all North American colonists after Parliament under William Pitt
8512-414: The dispossession of native inhabitants . As more states were admitted , a North–South division over slavery led to the secession of the Confederate States of America , which fought states remaining in the Union in the 1861–1865 American Civil War . With the victory and preservation of the United States, slavery was abolished nationally . By 1900, the country had established itself as a great power ,
8624-476: The early established cartridge arms was the Spencer repeating rifle , which Union forces used in the American Civil War . It was named based on the chamber dimensions, rather than the bore diameter, with the earliest cartridge called the "No. 56 cartridge", indicating a chamber diameter of .56 in; the bore diameter varied considerably, from .52 to .54 in. Later various derivatives were created using
8736-432: The end of their barrel life, whereby the rifling is worn down to a point where a rifle loses some of its accuracy , the choice to make a caliber or cartridge change is often done at the same time as when a new rifle barrel is fitted to the rifle by a gunsmith . There are a few important factors to consider when converting a rifle to a different caliber or cartridge. The action of the rifle should be long enough to contain
8848-580: The environment for labor unions to begin to flourish . This period eventually ended with the advent of the Progressive Era , which was characterized by significant reforms. Pro-American elements in Hawaii overthrew the Hawaiian monarchy ; the islands were annexed in 1898. That same year, Puerto Rico , the Philippines , and Guam were ceded to the U.S. by Spain after the latter's defeat in
8960-541: The federal government often applied policies of Indian removal or assimilation . The Trail of Tears (1830–1850) was a U.S. government policy that forcibly removed and displaced most Native Americans living east of the Mississippi River to lands far to the west. These and earlier organized displacements prompted a long series of American Indian Wars west of the Mississippi. The Republic of Texas
9072-606: The first nuclear weapons and used them against the Japanese cities of Hiroshima and Nagasaki in August 1945, ending the war. The United States was one of the " Four Policemen " who met to plan the post-war world , alongside the United Kingdom , Soviet Union , and China . The U.S. emerged relatively unscathed from the war, with even greater economic power and international political influence . After World War II,
9184-665: The first settlement of the Thirteen Colonies in Virginia in 1607. Clashes with the British Crown over taxation and political representation sparked the American Revolution , with the Second Continental Congress formally declaring independence on July 4, 1776. Following its victory in the 1775–1783 Revolutionary War , the country continued to expand westward across North America , resulting in
9296-655: The frangible armour piercing shell named Fap 27 mm x 145 mm ammunition/peb327 (DM103). In his book Typhoon, former RAF pilot Mike Sutton reported his 27 mm cannon jamming during a strafing run in Syria, against ISIS targets, while supporting Allied ground units. According to his book, the Typhoon was to be built, originally, without an internal gun, like the F-4 Phantom and the Harrier jump jet. However, while
9408-463: The integration of Army National Guard units and personnel into the U.S. Army and (since 1947) the U.S. Air Force. There are about 18,000 U.S. police agencies from local to national level in the United States. Law in the United States is mainly enforced by local police departments and sheriff departments in their municipal or county jurisdictions. The state police departments have authority in their respective state , and federal agencies such as
9520-421: The length of the barrel, with the use of chokes and back-boring. In the United Kingdom, "gauge" is referred to as "bore" and in the United States "bore" is referred to as "gauge", e.g. a "12-bore shotgun or 12-gauge shotgun" has a bore or gauge that can accommodate a lead sphere weighing 1/12th of a pound. The term caliber is used as a measure of length of artillery barrels from muzzle to breech, expressed as
9632-482: The military draft (leading to the end of conscription in 1973) and wide opposition to U.S. intervention in Vietnam (with the U.S. totally withdrawing in 1975). A societal shift in the roles of women was significantly responsible for the large increase in female paid labor participation during the 1970s, and by 1985 the majority of American women aged 16 and older were employed. The late 1980s and early 1990s saw
9744-612: The most attractive to the population are the most vulnerable. The U.S. is one of 17 megadiverse countries containing large numbers of endemic species : about 17,000 species of vascular plants occur in the contiguous United States and Alaska, and over 1,800 species of flowering plants are found in Hawaii, few of which occur on the mainland. The United States is home to 428 mammal species, 784 birds, 311 reptiles, 295 amphibians , and around 91,000 insect species. There are 63 national parks , and hundreds of other federally managed parks, forests, and wilderness areas , managed by
9856-402: The most common sizes encountered, although larger, smaller and intermediate sizes existed. In practice, though, significant variation occurred in the actual mass of the projectile for a given nominal shot weight. The country of manufacture is a significant consideration when determining bore diameters. For example, the French livre , until 1812, had a mass of 489.5 g (1.079 lb), whilst
9968-662: The most violent, the California genocide of thousands of Native inhabitants, lasted into the early 1870s, just as additional western territories and states were created. During the colonial period, slavery had been legal in the American colonies , though the practice began to be significantly questioned during the American Revolution. States in the North enacted abolition laws , though support for slavery strengthened in Southern states , as inventions such as
10080-426: The new cartridge, the magazine should also be able to hold the new cartridge, the bolt face should be the correct diameter and the extractor the correct size to hold the head of the new cartridge. The most common of these caliber conversions on rifles, are usually done to change from a parent cartridge to a new cartridge based on it, like when converting a rifle to a 6.5 mm Creedmoor from a 308 Winchester on which it
10192-408: The policy of redlining later adopted by the federal Home Owners' Loan Corporation . An explosion of technological advancement accompanied by the exploitation of cheap immigrant labor led to rapid economic expansion during the late 19th and early 20th centuries , allowing the United States to outpace the economies of England, France, and Germany combined. This fostered the amassing of power by
10304-574: The primary colonial grievances was a denial of their rights as Englishmen , particularly the right to representation in the British government that taxed them . To demonstrate their dissatisfaction and resolve, the First Continental Congress met in 1774 and passed the Continental Association , a colonial boycott of British goods that proved effective. The British attempt to then disarm the colonists resulted in
10416-405: The projectile may be inserted from the mouth to the base of the tube and seated securely adjacent the propellant charge with relative ease. The gap, called windage , increases the size of the bore with respect to the diameter of the shot somewhere between 10% and 20% depending upon the year the tube was cast and the foundry responsible. The relationship between bore diameter and projectile weight
10528-570: The rights of African Americans . National infrastructure, including transcontinental telegraph and railroads , spurred growth in the American frontier . From 1865 through 1917 an unprecedented stream of immigrants arrived in the United States, including 24.4 million from Europe. Most came through the port of New York City , and New York City and other large cities on the East Coast became home to large Jewish , Irish , and Italian populations, while many Germans and Central Europeans moved to
10640-614: The rocky Great Basin and Chihuahua , Sonoran , and Mojave deserts. In the northwest corner of Arizona , carved by the Colorado River over millions of years, is the Grand Canyon , a steep-sided canyon and popular tourist destination known for its overwhelming visual size and intricate, colorful landscape. The Sierra Nevada and Cascade mountain ranges run close to the Pacific coast . The lowest and highest points in
10752-402: The rough bore, leaving the "lands" behind. Good performance requires a concentric, straight bore that accurately centers the projectile within the barrel, in preference to a "tight" fit which can be achieved even with off-center, crooked bores that cause excessive friction, fouling and an out-of-balance, wobbling projectile in flight. Calibers fall into four general categories by size: There
10864-567: The same basic cartridge, but with smaller-diameter bullets; these were named by the cartridge diameter at the base and mouth. The original No. 56 became the .56-56, and the smaller versions, .56-52, .56-50, and .56-46. The 56–52, the most common of the new calibers, used a 50-cal bullet. Other black powder-era cartridges used naming schemes that appeared similar, but measured entirely different characteristics; 45-70 , 44-40 , and 32-20 were designated by bullet diameter to hundredths of an inch and standard black powder charge in grains . Optionally,
10976-504: The same bore diameter, often involves merely re-chambering the barrel to the new cartridge dimensions, if the rim diameter of the new cartridge matches that of the old cartridge. Converting a rifle to fire a different cartridge in a different caliber and bore as what it initially was, means that the barrel of the rifle will also need to be changed. Because many competitive precision rifle shooters often shoot thousands of rounds per year both for practice and competitions, and they more often reach
11088-573: The six service branches, which are made up of the U.S. Army , Marine Corps , Navy , Air Force , and Space Force . The Coast Guard is administered by the Department of Homeland Security in peacetime and can be transferred to the Department of the Navy in wartime. The United States spent $ 916 billion on its military in 2023, which is by far the largest amount of any country , making up 37% of global military spending and accounting for 3.4% of
11200-545: The sole authority of a state government. SDFs are authorized by state and federal law but are under the command of the state's governor . They are distinct from the state's National Guard units in that they cannot become federalized entities. A state's National Guard personnel, however, may be federalized under the National Defense Act Amendments of 1933 , which created the Guard and provides for
11312-543: The states are also represented by local elected governments , which are administrative divisions of the states. States are subdivided into counties or county equivalents , and further divided into municipalities . The District of Columbia is a federal district containing the U.S. capital, Washington, D.C. . The federal district is an administrative division of the federal government. Federally recognized tribes govern 326 Indian reservations . The United States has an established structure of foreign relations, and it has
11424-510: The structure and responsibilities of the national federal government and its relationship with the individual states. The U.S. Constitution is the world's oldest national constitution still in effect (from March 4, 1789). Composed of three branches, all headquartered in Washington, D.C., the federal government is the national government of the United States. It is regulated by a strong system of checks and balances . The three-branch system
11536-582: The world's fourth-longest river system , runs predominantly north–south through the heart of the country. The flat and fertile prairie of the Great Plains stretches to the west, interrupted by a highland region in the southeast. The Rocky Mountains , west of the Great Plains, extend north to south across the country, peaking at over 14,000 feet (4,300 m) in Colorado . Farther west are
11648-583: The world's second-largest diplomatic corps as of 2024 . It is a permanent member of the United Nations Security Council , and home to the United Nations headquarters . The United States is a member of the G7 , G20 , and OECD intergovernmental organizations. Almost all countries have embassies and many have consulates (official representatives) in the country. Likewise, nearly all countries host formal diplomatic missions with
11760-513: The world's third-largest land area , largest exclusive economic zone , and third-largest population , exceeding 334 million. Its three largest metropolitan areas are New York , Los Angeles , and Chicago , and its three most populous states are California , Texas , and Florida . Paleo-Indians migrated across the Bering land bridge more than 12,000 years ago, and formed various civilizations and societies . British colonization led to
11872-444: The world's oldest surviving federation, and its presidential system of national government has been adopted, in whole or in part, by many newly independent states worldwide following their decolonization . It is a liberal representative democracy "in which majority rule is tempered by minority rights protected by law ". The Constitution of the United States serves as the country's supreme legal document , also establishing
11984-553: The world's tornadoes occur in the country , mainly in Tornado Alley . Overall, the United States receives more high-impact extreme weather incidents than any other country. Extreme weather became more frequent in the U.S. in the 21st century, with three times the number of reported heat waves as in the 1960s. In the American Southwest , droughts became more persistent and more severe. The regions considered as
12096-575: Was annexed in 1845, and the 1846 Oregon Treaty led to U.S. control of the present-day American Northwest . Victory in the Mexican–American War resulted in the 1848 Mexican Cession of California, Nevada, Utah, and much of present-day Colorado and the American Southwest . The California gold rush of 1848–1849 spurred a huge migration of white settlers to the Pacific coast, leading to even more confrontations with Native populations. One of
12208-759: Was adopted on July 4, 1776. The political values of the American Revolution included liberty , inalienable individual rights ; and the sovereignty of the people ; supporting republicanism and rejecting monarchy , aristocracy , and all hereditary political power; civic virtue ; and vilification of political corruption . The Founding Fathers of the United States , who included Washington, Jefferson, John Adams , Benjamin Franklin , Alexander Hamilton , John Jay , James Madison , Thomas Paine , and many others, were inspired by Greco-Roman , Renaissance , and Enlightenment philosophies and ideas. The Articles of Confederation were ratified in 1781 and established
12320-583: Was elected the country's first president under the Constitution, and the Bill of Rights was adopted in 1791 to allay skeptics' concerns about the power of the more centralized government. His resignation as commander-in-chief after the Revolutionary War and his later refusal to run for a third term as the country's first president established a precedent for the supremacy of civil authority in
12432-604: Was severed following the widespread adoption of rifled weapons during the latter part of the 19th century. Guns continued to be classed by projectile weight into the mid-20th century, particularly in British service with guns, such as the 2-pounder , 6-pounder , and 17-pounder anti-tank weapons . However, this value no longer definitively related to bore diameter, since projectiles were no longer simple spheres—and in any case were more often hollow shells filled with explosives rather than solid iron shot. United States The United States of America ( USA ), commonly known as
12544-444: Was usually expressed as the weight of its iron shot in pounds . Iron shot was used as the standard reference because iron was the most common material used for artillery ammunition during that period, and solid spherical shot the most common form encountered. Artillery was classified thereby into standard categories, with the 3-pounder, 4-pounder, 6-pounder, 8-pounder, 9-pounder, 12-pounder, 18-pounder, 24-pounder, and 32-pounder being
#573426