A shotgun shell or shotshell is a self-contained cartridge loaded with lead shot or a shotgun slug which is designed to be fired from a shotgun.
Most shotgun shells are designed to be fired from a smoothbore barrel, but dedicated shotguns with rifled barrels may take a number of different rounds. A rifled barrel will increase the accuracy of slugs, but makes it unsuitable for firing shot, as it imparts a spin to the shot cup, causing a centrifugal force that makes the shot form a hollow "O" shape in flight. Non-lethal shotgun ammunition is available in the form of slugs made of low-density material, such as rubber. See shotgun specialty ammunition for more information.
Dual gauge · Conversion (list) ·
Bogie exchange · Variable gauge
Track gauge is a technical term used in rail transport to define the spacing of the rails on a railway track.
O scale (or O gauge) is a scale commonly used for toy trains and model railroading. Originally introduced by German toy manufacturer Märklin around 1900, by the 1930s three-rail alternating current O gauge was the most common model railroad scale in the United States and remained so until the early 1960s. In Europe, its popularity declined before World War II due to the introduction of smaller scales.
O gauge had its heyday when model railroads were considered toys, with more emphasis placed on cost, durability, and the ability to be easily handled and operated by pre-adult hands. Detail and realism were secondary concerns, at best. It remains a popular choice for hobbyists who enjoy running trains more than they enjoy other aspects of modelling, and collecting vintage O gauge trains is also popular - there is a market for reproduction and vintage style models also. A number of changes in recent years have addressed the concerns of scale model railroaders, making O scale more popular.
An automatic shotgun is an automatic firearm that fires shotgun shells and uses some of the energy of each shot to automatically cycle the action and load a new round. It will fire repeatedly until the trigger is released or ammunition runs out. Automatic shotguns have a very limited range, but provide tremendous firepower at close range.
Automatic shotguns generally employ mechanisms very similar to other kinds of automatic weapons. There are several methods of operation, with the most common being gas, recoil, and blowback operated:
Military technology is the collection of equipment, vehicles, structures and communication systems that are designed for use in warfare. It comprises the kinds of technology that are distinctly military in nature and not civilian in application, usually because they are impractical in civilian application, have no legal civilian usage, or are dangerous to use without appropriate military training.
It is common for military technology to have been researched and developed by scientists and engineers specifically for use in battle by the armed forces. Many new technologies came as a result of the military funding of science. Weapons engineering is the design, development, testing and lifecycle management of military weapons and systems. It draws on the knowledge of several traditional engineering disciplines, including mechanical engineering, electrical engineering, mechatronics, electro-optics, aerospace engineering, materials engineering, and chemical engineering.
A modern shotgun slug is a heavy lead or copper-covered lead projectile, with or without a plastic tip, that may have pre-cut rifling and that is intended for use in a shotgun and often used for hunting large game. The first effective modern shotgun slug was introduced by Wilhelm Brenneke in 1898, and his design remains in use today. Most shotgun slugs are designed to be fired through a choked smoothbore barrel; they must be self-stabilizing in the absence of rifling.
Earlier types of slugs were also used in 4 bore guns intended for hunting dangerous African game in the 19th Century. Such 4 bore guns were produced in both rifled and non-rifled versions. Similarly, modern shotguns have been produced with rifled barrels, or rifled choke tubes, and slugs designed to be fired from them use spin stabilization. As these specialized shotguns are far more accurate than a smoothbore gun, they also usually have a mount for an optical sight, such as a scope. Many of these slugs are saboted sub-caliber projectiles, resulting in greatly improved external ballistics performance.
Dual gauge · Conversion (list) ·
Bogie exchange · Variable gauge
A narrow gauge railway (or narrow gauge railroad) is a railway that has a track gauge narrower than the 1,435 mm (4 ft 8 1⁄2 in) of standard gauge railways. Most existing narrow gauge railways have gauges of between 610 mm (2 ft) and 1,067 mm (3 ft 6 in).
The United States of America (USA), commonly referred to as the United States (US), America, or simply the States, is a federal republic consisting of 50 states, 16 territories, and a federal district. The 48 contiguous states and the federal district of Washington, D.C., are in central North America between Canada and Mexico. The state of Alaska is the northwestern part of North America and the state of Hawaii is an archipelago in the mid-Pacific. The country also has five populated and nine unpopulated territories in the Pacific and the Caribbean. At 3.79 million square miles (9.83 million km2) in total and with around 316 million people, the United States is the fourth-largest country by total area and third largest by population. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries. The geography and climate of the United States is also extremely diverse, and it is home to a wide variety of wildlife.
Paleo-indians migrated from Asia to what is now the US mainland around 15,000 years ago, with European colonization beginning in the 16th century. The United States emerged from 13 British colonies located along the Atlantic seaboard. Disputes between Great Britain and these colonies led to the American Revolution. On July 4, 1776, delegates from the 13 colonies unanimously issued the Declaration of Independence. The ensuing war ended in 1783 with the recognition of independence of the United States from the Kingdom of Great Britain, and was the first successful war of independence against a European colonial empire. The current Constitution was adopted on September 17, 1787. The first 10 amendments, collectively named the Bill of Rights, were ratified in 1791 and guarantee many fundamental civil rights and freedoms.