Two options. 1: Single-Shot is once per Combat Turn, vs Semi-Automatic once per Action Phase. 2: Both are once per Action Phase, but Semi-Automatic gets the option of doing a burst for a Complex Action.
So here's my guesses:
SS: PERHAPS once per Combat Turn, likely just once per action phase.
SA: Either 1 bullet as Simple, or a 3-bullet burst as Complex Action.
BF: SB for a Simple Action, or LB for a Complex Action.
FA: LB for a Simple Action, or FB for a Complex Action.
Any weapon used in a Complex Action multiple Passes in a row has its previous recoil added up. So if you have a Semi-Automatic weapon with 2 Recoil compensation, that first Semi-Auto Burst will be fine but the next Initiative Pass you'd start taking penalties.
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Anyway, I missed the part where it says you can only do 1 Attack Action per Action Phase, which also applies to Spellcasting. This means Spellcasting, Melee and Ranged all do 1 attack per Initiative Pass now, which makes it easier to balance their combat potential.
Add to that the rumored Reaction+Intuition dodgepool against both melee and ranged attacks, and suddenly we got gunfights that actually last multiple Combat Turns, rather than a single Initiative Pass. It also makes that extra Initiative Pass that more valuable, since you can't just use it defensively, it also gives you a chance to exhaust an opponent's dodge pool so you can actually slaughter them faster.