Abstract: A spin-stabilized projectile adapted to be fired from a weapon barrel, includes a projectile body having a length dimension, a rear length portion, an ogive-shaped front length portion and an intermediate length portion situated between the rear and front length portions; a metal guide band circumferentially mounted on the projectile body; and an undercut provided circumferentially in the intermediate length portion to define an annular chamber with an inner surface of the weapon barrel during travel of the projectile in the weapon barrel upon firing for effecting a pressure equalization of propellant gases flowing past the metal guide band to center the projectile within the weapon barrel.