Just wondering how Auto Fire interacts with other qualities. Say I give a blast weapon auto fire. Does then open up the door to activating multiple blasts from one attack? (2adv to activate AF and 4adv to do blast, burn, concuss etc twice?)

It would be Advantages per whatever effect. So an autofire blast weapon, like a Mk 19 grenade launcher, would require a pair of Advantages for a second shot to hit, and 4 more for both of the two shots to activate Blast, for 6 total.

Some Qualities don't stack either, so activating them multiple times on the same target serves no purpose, but if your hitting multiple targets then obviously each activation affects different targets. Same with the Blast, it seems obvious but if your targeting 2 different groups and activating blast twice then each activation is for the seperate groups.

Autofire and blast is a particularly interesting combination...

3x Adv to trigger blast to hit all targets in Engaged with the primary
2x Adv to autofire & hit a second target
3x Adv to trigger blast again...

Let's say there are 4 targets, A-D.

A is primary target, 7 advantage, 1 success, 1 triumph. Trigger blast, so the homebuilt blast 5 autofire damage 5 pistol...
Triumph to crit A, doing 5+(1 s)+(blast 5)=11 damage... and putting a 5 pointer on B, C, & D...
Hit B. Blast on B. B also takes an 11 point hit, and A, B, & C all take 5 pointers.

So A takes 11+5-(2* Soak)
B takes the same.
C & D both take 10 - (2 * soak)

But some would simply add the blasts without applying soak again.

And Blast versus minion groups... does soak get applied once to the blast once? or does each member of the group get soak versus it?
(I myself don't really care if there's an official answer, because I use the each soaks the blast individually, as a means of letting blastsclear out weak minions pretty fast. YMMV.)

Blast is only 2A if you hit. It's 3 if you missed. But your on point, it's potent for sure. Although I do think a low crit autofire weapon is more flexible against various foes.

So A takes 11+5-(2* Soak)

B takes the same.

C & D both take 10 - (2 * soak)

2*Soak is only true if the Soak is 5 or less in this case. If the Soak was 6, then A wouldn't take 11+5 - 2*6 = 4, A would take 11 - 6 + Max(5 - 6,0) = 5

And Blast versus minion groups... does soak get applied once to the blast once? or does each member of the group get soak versus it?

(I myself don't really care if there's an official answer, because I use the each soaks the blast individually, as a means of letting blastsclear out weak minions pretty fast. YMMV.)

Should a group of minions be treated as a group of individuals who happen to share one wound pool, or as a single entity?

That is to say, if a blast goes off in the middle of a group of minions

-- should each minion, individually, take the blast damage, soak it, and apply the remainder to their shared pool, or

-- does the group as a whole get hit by the blast, take the damage, soak it once, and then apply the remainder (and if so, then does the group being the primary target exclude the group from being affected by the blast)?

Or is there some other methodology?

Answered by Sam Stewart:

The first option would be more thematically appropriate. That being said, if the minions were particularly spread out (if you had a group of four with two each behind two separate barricades, for example), I'd rule that some of the minions couldn't be hit by the blast damage. It does make grenades quite effective against minion groups; but that's sort of the idea in any case.

IIRC, when you activate Blast on a weapon, the Blast damage does not apply to the primary target — you’ve already hit them with the damage before activating Blast. The point of Blast is to also be able to hit the others who might be within Engaged range of the primary target.

If you miss with the attack but get enough Advantage, then you can activate Blast and hit both the primary target with the Blast (so this acts as a second opportunity to hit them, albeit for less damage), as well as those who are in Engaged range with him.