Kami-Kaze wrote:

Hrm. The book mentions that smart ammo can be combined with other ammo types (other than a select few). Does that include with other smart ammo? If so, how many modifications can be made on a single bullet? Homing Zero AP Rounds, for example. On a related note, is there any particular reason to take Zero rounds over Homing rounds?

No. Unless stated otherwise, you cannot add multiples of the same modification to anything. Only two modifications can be on any given type of ammo... one valid type of smartgun mod and one of the other mod types. You cannot combine multiple smart ammo types together, nor can you have normal normal mods on the same ammo. As for Zero rounds, I'm pretty sure the bonuses stack. The second attack (the description is a bit misleading... the modifiers are added per shot or burst, not by bullet) gets a +10 bonus, the third a +20 bonus, et cetera. Remember, though, that the bonuses only last for a single action turn (you reset to +0 at the start of the next turn for Zero ammo bonuses), and that the total of ALL bonuses (positive or negative) can never alter your target number by more than ±60.