A projectile has fins that are hingedly coupled to a fuselage. The fins are configured to wrap around the fuselage, assuming a location as close as possible to the fuselage, when the projectile is in a gun or launch tube. The fins have spiracles, one or more openings in each of the fins that allow pressurized gases to pass therethrough. The spiracles may be always open, or may open only when there is a sufficient pressure differential between the sides (major surfaces) of the fins. The spiracles allow release of pressurized gases that are trapped between the fins and the fuselage during the launch process. This prevents undesired outward movement or bending of the fins when the projectile reaches a muzzle brake during launch, a structure which causes a sudden release of pressure at radially outer locations of the launch tube.