Here are some current drag models used in small arms ballistics:

G1 - Standard model, Flat Based with 2 caliber (blunt) nose ogive

G2 - Special model for a long, conical point banded artillery projectile
       with a 6 deg boat tail.  Not generally applicable to small arms.

G5 - For Moderate (low base) Boat Tails - 7 deg 30' Tail Taper
       with 6.19 caliber tangent nose ogive
      
G6 - For flat based "Spire Point" type bullets - 6.09 caliber
       secant nose ogive

G7 - For "VLD" type Boat Tails - long 7 deg 30' Tail Taper
       with 10 caliber tangent nose ogive 

G8 - Flat base artillery projectile with similar nose design to G7.
       Also applicable to small arms projectiles

GS - For round ball - Based on measured 9/16" (.563") spherical projectiles
       as measured by the BRL (Form Factor = 1 with GS, not 2 with G1)
       Smaller sphere characteristics are effectively identical.

RA4 - For 22 Long Rifle. 

GL - Traditional model used for blunt nosed exposed lead and hollow point
       bullets, identical to G1 below 1400 fps

GI - Converted from the original Ingalls tables

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GS1929 - BRITISH 1929 ROUND SHOT, MAYBE 9/16" ROUND BALL.
