G1 vs. G7 Ballistic Coefficients — Which Is Right for You?
G1 and G7 refer both refer to aerodynamic drag models based on particular "standard projectile" shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferrable for flat-based bullets, while G7 is ordinarily a "better fit" for longer, boat-tailed bullets.
C'est en anglais mais. Ça provien du site de berger
en gros c'est un modèle de la trainée de différante ''shape'' de boulets
Je sais que G1 c'est pour les boulets a bout plat et le G7 pour les boulets boat tail
Le G2 et le G5 je ne sais pas c'est quoi, quelqu'un peut nous éclairer?
J'ai trouver ceci sur wiki:
G1 or Ingalls (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)
David