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Shot is a collective term for small balls or pellets, often made of lead. These were the original projectiles for shotguns and are still fired primarily from shotguns, although shot shells are available in many pistol calibers in a configuration called "bird shot" or "rat-shot". Lead shot is also used for a variety of other purposes such as filling cavities with dense material for weight/balance. Some versions may be plated with other metals. Lead shot was originally made by pouring molten lead through screens into water, forming what was known as "swan shot", and, later, more economically mass-produced at higher quality using a shot tower. The ''Bliemeister method'' has supplanted the shot tower method since the early 1960s. == Manufacture == Producing lead shot from a shot tower was pioneered by William Watts of Bristol who adapted his house on Redcliffe Way by adding a three-storey tower and digging a shaft under the house through the caves underneath to achieve the required drop. The process was patented in 1782. The process was later brought above ground through the building of shot towers. Molten lead would be dropped from the top of the tower. Like most liquids, surface tension makes drops of molten lead become near-spherical as they fall. When the tower is high enough, the lead droplets will solidify while still dropping and thus will retain their spherical form. Water is usually placed at the bottom of the tower, causing the lead to be cooled immediately after dropping. Roundness of manufactured shot produced from the shot tower process is graded by forcing the newly produced shot to roll accurately down inclined planes. Unround shot will naturally roll to the side, for collection. The unround shot was either re-processed in another attempt to make round shot using the shot tower again, or used for applications which did not require round shot (e.g., split shot).〔 The hardness of lead shot is controlled through adding variable amounts of tin, antimony and arsenic, forming alloys.〔 This also affects its melting point. Hardness is also controlled by the rate of cooling that is used in manufacturing lead shot. The ', named for inventor Louis W. Bliemeister of Los Angeles, CA, (, dated April 11, 1961) is a process for making lead shot in small sizes from about #7 through about #9. In this process, molten lead is dripped from small orifices and dropped approximately into a hot liquid, where it is then rolled along an incline and then dropped another . The temperature of the liquid controls the cooling rate of the lead, while the surface tension of the liquid and the inclined surface(s) work together to bring the small droplets of lead into highly regular balls of lead in spherical form. The size of the lead shot that is produced is determined by the diameter of the orifice used to drip the lead, ranging from approximately 0.018-inches for #9 lead shot to about 0.025-inches for #6 or #7.0 shot, while also depending on the specific lead alloy that is used. The roundness of the lead shot depends on the angle of the inclined surfaces as well as the temperature of the liquid coolant. Various coolants have successfully been used, ranging from diesel fuel to antifreeze and water-soluble oil. After the lead shot cools, it is washed, then dried, and small amounts of graphite are finally added to prevent clumping of the lead shot. Lead shot larger than about #5 tends to clump badly when fed through tubes, even when graphite is used, whereas lead shot smaller than about #6 tends not to clump when fed through tubes when graphite is used. Lead shot dropped quickly into liquid cooling baths when being produced from molten lead is known as "chilled lead shot", in contrast to "soft lead shot" which is produced by molten lead not being dropped as quickly into a liquid cooling bath. The process of rapidly chilling lead shot during its manufacturing process causes the shot to become harder than it would otherwise be if allowed to cool more slowly. Hence, chilled lead shot, being harder and less likely to deform during firing, is preferred by shotgunners for improving shot pattern densities at longer (> 30 yard) ranges, whereas soft lead shot, being softer and more likely to deform during firing, is preferred for improving shot pattern densities at very close (< 20 yard) ranges as the softer and now deformed shot scatters more quickly when fired. Soft lead shot is also more readily deformed during the firing process by the effects of chokes. The manufacture of non-lead shot differs from that of lead, with compression molding used to create some alloys. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Shot (pellet)」の詳細全文を読む スポンサード リンク
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