It's a little more complicated than that seeing as various authors will use an equally varying amount of methods to create projectile attacks. The two primary types, however, are the projectile sctrl and helper based projectiles. Due to the varying types out there, priority interactions will be very inconsistent as a result. If you want more control over your projectile's priority, I'd suggest making it a helper with a hitoverride that returns to its own state if you want it to overpower both projectile state controllers and helper projectiles.
