Very-low-drag bullet

Very-low-drag bullets (VLD) are 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 target shooters, including benchrest competitors, but hunters have also benefited. Most VLD bullets are used in rifles.

By increasing the bullet's ballistic coefficient, the bullet decelerates less rapidly. This flattens the projectile's trajectory somewhat and also markedly decreases the lateral drift caused by crosswinds. The higher velocity at impact delivers more kinetic energy.

The development of VLD bullets has focused on the following main factors:

• the production of bullets with concentric and coincident centers of form and centres of mass
• bullet design incorporating a secant ogive, tangent ogive, Von Kármán ogive or Sears-Haack profile in the bullet's nose area
• the use of carefully tapered bullet heels, or boat-tails
• a cavity or hollow in the bullet nose (hollow point) to shift the projectile's centre of gravity rearwards

The resulting projectile should be very "slippery" - i.e. well streamlined - for easier passage through the air. Consistency in bullet production, allied to consistency in the assembly of cartridges - i.e. quality control - should give excellent shot-to-shot consistency.

The principles of bullet design and flight are classically set out in Mann, F.W.: The Bullet's Flight From Powder to Target: Ballistics of Small Arms (1942 and other reprints).

A collection of modern mono-metal solid VLD bullets can be seen at the LM Class Bullets and GS Custom Bullets websites. Alloys like copper nickel, tellurium copper and brass are used for turning these projectiles on precision CNC lathes. Producing accurate bullets this way is not easy. To guarantee consistency and hence accuracy professional quality control during and after production is needed.

See also

• Drag (physics)
• Parasitic drag
• Boundary layer
• Drag coefficient
• Nose cone design

References

Mann, F.W.: The Bullet's Flight From Powder to Target: Ballistics of Small Arms (1942 and other reprints)

External links

• General Notes on Bullet Design
• VLD bullets on long-range varmints
• Haack Minimum Drag Bullet
• Geschoßformen kleinsten Wellenwiderstandes by W. Haack, Bericht 139 der Lilienthal-Gesellschaft (1941)
• What is the Maximum Length of a spinstabilized Projectile? by Mr. Beat Kneubühl
• LM Class Bullets, very high BC bullets for windy long Ranges