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The very-low-drag bullet (VLD) is primarily a small arms ballistics development of the 1980s–1990s, driven by shooters' desire for bullets that will give a higher degree of accuracy and kinetic efficiency, especially at extended ranges. To achieve this, the projectile must minimize air resistance in flight. Demand has been greatest from military snipers, long range target shooters, including F-class and benchrest competitors, but hunters have also benefited. Most very-low-drag bullets are used in rifles. Bullets with a lower drag coefficient decelerate less rapidly. A low drag coefficient flattens the projectile's trajectory and also markedly decreases the lateral drift caused by crosswinds. The higher impact velocity of bullets with low drag coefficients means they retain more kinetic energy. ==Development== The development of very-low-drag bullets has focused on the following main factors: * the production of bullets with concentric and coincident centres of pressure and centres of mass * bullet nose design incorporating a secant ogive, tangent ogive, Von Kármán ogive or Sears-Haack profile * the use of tapered bullet heels, also known as boat-tails * a cavity or hollow in the bullet nose (hollow point) to shift the projectile's centre of gravity rearwards * To reduce damage to the employed barrel and increase muzzle velocity, some modern mono-metal very-low-drag bullets are bore-riding bullets, in which thin driving bands are the only parts that are etched by the barrel's lands. The use of driving bands originates from artillery shells and to use these driving bands correctly requires projectiles and barrels to be precision-fitted to each other. The resulting projectile should be streamlined for easier passage through the air. Consistency in bullet production, allied to consistency in the assembly of cartridges (quality control) should give excellent shot-to-shot consistency. The principles of bullet design and flight are classically set out in F.W. Mann's ''The Bullet's Flight From Powder to Target: Ballistics of Small Arms''.〔 * Mann, F.W.: The Bullet's Flight From Powder to Target: Ballistics of Small Arms (1942 and other reprints)〕 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「Very-low-drag bullet」の詳細全文を読む スポンサード リンク
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