One MASTER object or 15+ objects?

My game will have around 15 projectiles and I was wondering if I should make one master projectile with lots of animations OR 15 objects with 1 animation(code with family)?

This depends on whether you need to treat the projectiles differently.

I guess that each projectile will have different effects on impact.

If that is the case (instead of just graphical differences), I would highly recommend that you use several Sprites since that will make it easier for you to treat them differently in events.

Using 15 separate objects (with events referencing a family) is better for memory management. Objects are either fully loaded in to memory, or not at all. So if you use a master object, using just one kind will load all kinds in to memory, whereas using separate objects allows only the used objects to be loaded in to memory.

Thanks for the reply, would it make a difference in bandwidth usage (multiplayer object sync)?