Drag Models Commonly used for Small Arms Ballistics:
G1.1 = Standard Model. Flat Based with 2 caliber, (blunt) nose ogive.
G5.1 = For Moderate (Low Base) Boat Tails – 7°, 30’ Tail Taper with a 6.19 caliber tangent nose ogive.
G6.1 = For Flat Based Spire Point type bullets – 6.09 caliber secant nose ogive.
G7.1 = For VLD type Boat Tail type bullets – Long 7°, 30’ Tail Taper with 10 caliber secant nose ogive.
GS = For Round Ball – Based on Measured 9/16” Spherical Projectiles.
RA4 = For .22 Long Rifle. Identical to G1 at below 1,400FPS.
GL = Traditional Model used for Blunt Nose exposed Lead Bullets. Identical to G1 at below 1,400FPS.
G1 = Converted from the original Ingalls Tables. G1 projectiles are Flat Base Bullets with 2 caliber nose ogive and are the most common type of bullet.
Found here....https://kestrelmeters.com/pages/g1-g7-ballistic-coefficients-what-s-the-difference