The drag is reduced by a gas generator located on the base of the projectile. Once ignited, the gas generator bleeds hot gas into the projectile's wake, which causes the flow of air at the base to be less turbulent. The decrease in turbulence reduces base drag, which typically accounts for 50 percent of total drag.
A gas generator located on the base of a projectile reduces drag by introducing hot gases into its wake, resulting in reduced turbulence and subsequently lower base drag, which is usually around 50% of the total drag.