Smooth bore weapons

With very few exceptions the inner surface of a shotgun barrel is smooth hence shotguns are called smooth bore weapons. The caliber of a shotgun is usually expressed as its bore or gauge the most common are 12, 16, and 20 bore with the 12 bore by far the most popular. Bore refers to the number of lead balls of bore diameter that weigh 1 lb.3 Smaller-diameter shotguns are usually described by the internal diameter of the barrel, for example,. 410 . 

Here primers and igniters are separate elements and not in one piece as for igniting proplnts in gun howitzer cannons, and in recoilless rifles. The weapons known as 60-mm Mortar Cannons M2 M19 arid 81-mm Mortar Cannons Ml M29 are smooth-bore. 

Accdg to Maj Hobart (Ref 3)> die ides of fin stabilization is much older than spin stabilization. This is because the earliest weapons were smooth-bore and they could use finned projs, while spin projectiles required rifled weapons which were notin-vented until about 1500. The earliest fin-stabilized projectile was an arrow and then fireworks projs, which could be called rockets. The earliest projs fired from smooth-bore barrels of small arms or cannons were like balls and they did not have any stabilizing attachments. However, accdg to the description given in Milimet Manuscript of 1326, now in Christchurch, Oxford, the earliest cannon, known as pot de feu (fire pot) was fin-stabilized (See also Voi 2 of Encycl, p C26fL)... 

Little David . The latter weapon used a shell with pre-engraved band(Ref 12,pp 172-3)- As examples of smooth-bore breech-loaders may be cited the 2-in Mortar of Brit design installed on some US tanks used during WWII and the 75mm Infantry Assault Mortar, M1923. As an example of rifled-bore breech-loaders may be cited the 12-in Seacoast Mortar, Model 1890, which is now obsolete(Refs 20 21)... 

The projectiles(rockets) launched from these weapons are self-propelling, travelling toward their targets by means of gases escaping from combustion chambers within the rockets There are two types of rocket launchers a)0pen Tube Type Launcher consists of one or severaI(Multiple Launcher) smooth-bore tubes each equipped at the base end with an electric... 

Small arms may be taken to mean weapons with a bore of less than 2-5 cm, whether the barrel is smooth or rifled. Compared with larger weapons, they have light bullets or shot and have relatively short barrels. Propellants used must therefore be fast burning and have small web thickness. The factors which determine design of powder depend also on the individual characteristics of the weapons. 

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