Multi Attack, minor action. Augments and gear may allow characters to make more than one attack per action. Each attack must be made against a different target.
Use half the appropriate dice pool for each attack.
Melee: Characters may make 1 additional attack per Initiative Die they roll. All targets must be within melee range. Some weapons (double bladed weapons, etc) may also provide additional attacks.
Firing Modes
When using Ranged Weapons in the primary hand, additional attacks must be against targets within X meters of each other. Ranged weapons held in the off hand do not gain the benefit of additional attacks from firing mode.
SS: Base AR, Base DV, no additional attacks. 1 ammo
SA: -2 AR, and: +1 DV OR +1 additional attack. 2 ammo
BF: -4 AR, and: +2 DV OR +2 additional attacks. 4 ammo
FA: -6 AR, and: +3 DV OR +3 additional attacks. 10 ammo
Dual Wielding: +1 additional attack, with that weapon. When dual wielding ranged weapons with firing modes, characters must choose between making an additional attack with the off hand OR making additional attacks with the firing mode of the primary hand. Targets do not need to be within X meters of each other when using additional attacks from dual wielding. Additional attacks made from the off hand may be made against the same target as attacks from the primary hand.
Ambidextrous quality: Offhand may use Edge, and may gain the benefit of additional attacks from firing mode. Characters still may not gain the benefit of additional attacks from firing mode in both hands at the same time.
(maybe-possibly-haven't thought about it much) Gun Kata: Ambidextrous characters may gain the benefits of additional attacks from firing mode in both hands at the same time (just an idea, it'd be cool to make additional attacks an effective path of high level growth)
Anticipation: Use full dice pool when making multiple attacks.
My reasoning: Splitting the dice pool at any time is usually a bad idea. Focusing fire is normally preferred, it's a basic, effective RPG tactic. That's why I only ever limit it to one split, regardless of number of targets. This mode of attack still has to have a chance to be effective. More than one split, at the dice pool numbers Shadowrun uses, almost always results in completely missing everything. Splitting once is risky at dice pools of 12 and under. At 16 they can be reliable in non-critical situations, at 20 it's pretty reliable in most situations except against really heavy hitters. I have a player who is just starting to think about multiple attacks now that his firearms pool is 18.
I initially thought about giving a flat dice pool penalty for multiple attacks, but settled on splitting because it's a penalty that grows with the pool, and also doesn't sound as bad as "-6" which is what it often is.
Since splitting multiple times per target was a self-limiting mechanic, I tied # of attacks to firing mode and other augments people can chase, something other people are doing too.
The only thing I think is wrong with Anticipation is the lack of target cap. So I didn't change it.
Edit: added clarifications and cases for multiple attacks vs one target