As far as i know there are no specific rules for Projectile Weapons in SD.
Probably a point to debate about.
But for simplicities sake i would stick to the Energy weapons rules.
On the other Hand Projectiles have a far lower effective Range (due to the fact that the projectiles can not travel at the speed of light.)
Another question that raises its ugly head is naturally how to resolve the hailstorms of Projectiles the Galactica throws at enemy fighters in game terms.
Probably the damage value represents a whole burst of Projectiles.
"Space may be the Final Frontier, but it's made in a Hollywood basement"
Red Hot Chili Peppers "Californication"
"per aspera ad astra"
Seneca