It might or might not be OK to split a 3 bullet burst from a BF weapon. It does not make sense from a real life point of view to split it (if you have not tried to fire a weapon in 3 bullet burst fire mode in real life - i have - just try it in some random FPS...) and there are no game rules that explain how it is resolved.
This is not real life though. Many game situations, and rules, make absolutely no sense, if viewed through the "real life" filter. Real Life doesn't typically included augmented reflexes, smartguns, cyberlimbs, etc. . . and there are game rules. . .
The game presents all the rules you need in order to split a burst among multiple targets.
p.179 Under each of the Semi-Automatic Burst, Burst Fire, Long Burst, and Full Auto, it lists . . . "Can take advantage of the Multiple Attacks Free Action to fire at multiple targets with the same burst."
p.180 shows the Firing Mode chart, how many bullets each burst uses, and the Defense Modifier.
p.180 Also has the
Not Enough Bullets Sidebar, which explains that for each bullet a listed burst is short by, the Defense penalty is reduced by one.
p. 196 In Multiple Attacks, it explains about the maximum number of attacks you can make in a single phase being limited by Skill/2. It also explains that you combine all modifiers (range, wounds, recoil, and even bonus Edge dice)
Before you split your dice pool as evenly as possible.
This is really all you need. If you have a skill of 6, and want to split a Long Burst (6 rounds), the most you can split it between is 3 targets. Use 2 bullets to each target, split your dice pool by 3, and roll each attack separately.
Are there rules for "walking" your fire? No. But there doesn't have to be. Are the rules stating how far targets can be from eachother? No, but there doesn't have to be. The GM can make those determinations. If the GM wants to dictate that a bullet is lost for every meter you have to skip (like how it was in SR3 p.116), then the GM will say so.
But note, even in SR3, Smartguns never wasted bullets. The Smartgun picks up the gap, and that you aren't shooting at anything in that gap, and so the smartgun halts fire until you are back on target again.
"When engaging multiple targets in full-auto mode, the attacker must “walk” the fire from one target to the next. This means that one round is wasted for every meter of distance between the two targets. Smartguns never waste rounds"Why does SR5 not need this rule? because SR5 handles damage and attack differently. In SR3, if you had a dice pool of 9 dice, and you tried to split your attack, you would roll 9 dice for the first target with a TN of 4 (just to grab one). For your second target, you would still roll all 9 of your dice, but now with a TN of 6 (each additional target increased your target number by +2), and you would roll all 9 dice against your third target, but now with a TN of 8.
And the damage mattered based on how many bullets you fired at a target, which is why they recommended firing a burst at each target. If your weapon did 8M (Moderate Wound, with a TN of 8 to stage down the damage), the power would go up by +1 for every bullet, and the damage level would increase for every 3. So a 3rnd burst would take that 8M up to 11S (Serious Wound, needing 11's to stage down the damage). Power went up by +1 per bullet, damage level went up one category for every 3 bullets. So, they even had rules for bursts without enough bullets then too.
So your penalty in earlier editions from splitting attacks came from losing bullets, and each additional target being harder to hit. You would almost always hit your primary target, and maybe even your secondary target. But when you counted lost bullets from "walking" it could mean the difference between harder to resist Serious wounds, to easily resisted Moderate wounds.
SR5 handles damage and attack differently. Now, you are simply dealing a number of boxes equal to damage code + net hits. The larger a burst, the less dice they defend with, which in theory means you increase your likelihood of dealing more damage. By Splitting your bursts, your penalty in SR5 is that you are rolling less dice to attack, and their defense penalty is lower, because you are firing less bullets at them. With that same dice pool of 9, you are going to be rolling 3d6 against each target, and they are going to be rolling practically their full defense pool.. -1 each for 2 round bursts coming their way. Also, with fewer dice, your chances of a Glitch or Critical Glitch are higher. So, ultimately, in SR5, Splitting bursts makes you more likely to
miss your target. You don't need to further complicate matters by trying to decide if Target 2 is a little too far from Target 1. Or if the gap between Target 2 and 3 means you should lose another bullet. Keep it simple, use common sense, and GM determinations for that.
Of course, Several will say (and have already said) that there aren't enough rules, that there needs to be errata, that it needs to be more complicated. If you feel this, then by all means, continue waiting. But when you get down to it, there is enough in the book, and it works just fine in practice.
