The rangers are getting some much needed answers from a coder, in a very good thread posted in the EQ2 rangers forum. The thread discusses the various kinds of procs and what it all means for you, the ranger:

Generally, the procs that will be triggered by your bow say something generic like 'On a successful attack' or 'When target is damaged in combat' or specifically for ranged weapons: 'On a successful ranged attack' or 'When target is damaged with a ranged attack'. You shouldn't get procs that are triggered by spells or spell attacks or 'melee' weapons.

There is some great info in this thread, and it looks to be a helpful discussion for this class, so be sure to check it out!