Several drag curve models optimized for several standard projectile shapes are however available. The resulting fixed drag curve models for several standard projectile shapes or types are referred to as the:
G1 or Ingalls (flatbase with 2 caliber (blunt) nose ogive - by far the most popular)
G2 (Aberdeen J projectile)
G5 (short 7.5° boat-tail, 6.19 calibers long tangent ogive)
G6 (flatbase, 6 calibers long secant ogive)
G7 (long 7.5°
boat-tail, 10 calibers tangent ogive, preferred by some manufacturers for very-low-drag bullets[5])
G8 (flatbase, 10 calibers long secant ogive)
GL (blunt lead nose)
https://en.wikipedia.org/wiki/External_ballistics