Double Barreled Pistol / Musket attacks or actions question

[CryosFirerush]

I've been debating with one of my players, who's playing a gunslinger, for some time now about how double barreled pistols, and double barreled muskets by assocation, work since the wordings are confusing on both and consulting the "Surpassing even the boss" guide to gunslingers has only confused me more.

Is shooting both barrels of the double barreled pistol or the double barreled musket a standard action or is it an "attack" and therefore allowed to be used mutiple times in a full round attack if the gunslinger can reload as a free action (with rapid reload and alchemical cartridges), letting you shoot a total of eight bullets, four pairs of two, once you have four attacks per round?

Please I don't want a debate started or an argument, I'm hoping a Paizo admin will answer me and provide the solid rule on this before my player reaches level 6 and this becomes a serious debate at the table. I've looked everywhere and people argue and disagree about this so much that I can't figure out the answer.

[Heretek]

There was an errata a while back. Shooting both barrels is a standard action.

"In the Musket, Double-Barreled Musket
entry, in the first sentence, change everything after the
semicolon to “each barrel can be shot independently
as separate attacks, or both can be fired at once as a
standard action (the attack action).”

This counts for the pistols as well.

[CryosFirerush]

They really should update the errata on the site and in both ultimate combat and ultimate equipment

[Bartholomäus]

It's updated in Ultimate Combat, but errata can only be issued when a new printing is released, so it won't show up in Ultimate Equipment for a while.

Hopefully this ends the debate in your game.

[Jeff Merola]

Also note that there was a mistake in the errata and only the Musket was actually updated, but all of the double barreled weapons should use the new wording.