There is some question/debate about how the Gunslinger's level 11 ability "Lightning Reload" (LR) interacts with the feat "Rapid Reload" (RR) for the purpose of multiple attacks.
The question arises from the use of the phrase
"can reload a single barrel".
One can interpret this to mean that LR can only be used once per round (provided at least 1 grit point). For example, if a gunslinger has RR: Pistol, she can reload once per round using a free action via LR, but any further reloads require alchemical cartridges.
On the other hand, one can also interpret this to mean that she can only load one barrel, as many times as she wants (as free actions). Let me clarify, LR says she can reload ONE barrel as a free action. Typically you receive unlimited free actions per turn (within reason).
So logically she should be able to reload that same one barrel multiple times per round as free actions. What this wording prevents is reloading firearms with more than one barrel as a free action. For example, she could only reload one barrel of a double-barrel pistol or pepperbox. But I suppose she could simply load all of the barrels of a pepperbox with multiple free actions.
So the question at the heart of this is whether an 11th level Gunslinger should be able to make full-attacks each round without using Alchemical rounds (provided she has RR and 1 grit point)?
Asked another way, does the phrase "can reload a single barrel" mean she can only reload one barrel per round, or only one barrel per free action?