Question that came up in our game last night.
The party gunslinger was dueling a swashbuckler to see who could disarm the other first. The gunslinger used her targeting ability which reads:
"Targeting (Ex): At 7th level, as a full-round action, the gunslinger can make a single firearm attack and choose part of the body to target. She gains the following effects depending on the part of the body targeted. If a creature does not have one of the listed body locations, that part cannot be targeted. This deed costs 1 grit point to perform no matter which part of the creature she targets. Creatures that are immune to sneak attacks are immune to these effects.
Arms: On a hit, the target takes no damage from the hit but drops one carried item of the gunslinger’s choice, even if the item is wielded with two hands. Items held in a locked gauntlet are not dropped on a hit.
Head: On a hit, the target is damaged normally, and is also confused for 1 round. This is a mind-affecting effect.
Legs: On a hit, the target is damaged normally and knocked prone. Creatures that have four or more legs or that are immune to trip attacks are immune to this effect.
Torso: Targeting the torso threatens a critical on a 19–20.
Wings: On a hit, the target is damaged normally, and must make a DC 20 Fly check or fall 20 ft."
Gunslinger targeted her arm to cause her to drop her weapon.
The swashbuckler has the Subtle Blade ability which makes her immune to disarm, steal, and sunder combat maneuvers. Would the targeted strike be considered a disarm? It seems a little odd to me that they would give the Gunslinger(and the swashbuckler) a 7th level ability that overrides the 11th level ability of the Swashbuckler.
You concern is one the things I chiefly hate about the gunslinger and swashbuckler classes, in that they both get abilities that break the normal set of rules.
Saethori is correct, it is not technically a disarm and so the ability to be incapable of being disarmed doesn't apply. Nor do bonuses against being disarmed. As a GM and player I find it very cheap and really don't like these sorts of abilities that go outside the normal CMB/CMD system and invalidate abilities that do work within that system.
But those however, are the rules.
Essentially, being disarmed is dropping your weapon but not all dropping your weapon is being disarmed. Consider an ability that causes the target to fall prone. That's not a trip despite both having the same result. So, if you used Targeting on their leg, you wouldn't benefit from Improved or Greater Trip, though you could use Vicious Stomp. Likewise, Targeting at the arm isn't a disarm so Subtle Blade won't protect against it, but also you couldn't use abilities that give bonuses to Disarm attempts like Improved/Greater Disarm.
Well, to be fair, as was pointed out above, "Disarm" is about actively wresting the weapon out of their hand while forced drops are about removing their capacity to hold on to the weapon. If someone strikes your arm in a way that your grip loosens reflexively or due to injury, or if grease makes the weapon too slippery to hold on to, or if Heat Metal heats up the weapon to the point where you reflexively let go, that doesn't count as a disarm and, realistically, a Weapon Master's training isn't going to allow him to overcome his weapon turning red-hot in his hand or grease removing the friction that prevents it from sliding out of his grip. Immunity to disarm means your fighting style and technique and grip is such that when the enemy is trying to lever the weapon out of your hand with their own techniques and strength, they simply cannot succeed; but they can still cut off your hand or arm with a called shot.
The general consensus I am seeing is that yes it would disarm. I'll go with that. I am with Claxon though. It overrides part of a fighters capstone, which is a little ridiculous.
On a similar note, does anyone know if officially disarming someone breaks a weapon cord?
Nothing states that it does so no, it doesn't. If you are disarmed but you have a weapon cord, you can just use a move action to quickly retrieve your weapon. It also protects you from the effect of Greater Disarm. In order to cut the cord, you'd need to sunder it. The only real corner case is if you disarm while unarmed and want to invoke the "auto pickup" clause for disarm. In that circumstance, I'd say that the weapon cord probably prohibits that since the weapon can't travel more than 2 feet from its owner due to the cord so even if you tried to grab it, the cord would "yank" it out of your hand as you tried to back away.
The fact that it's not a disarm (and therefor easier to do successfully) is offset by the fact that it's a Full-Round Action that costs a resource (albeit a refillable one) instead of a single strike that could be part of a normal Full Attack. You're giving up the opportunity to do damage in favor of making an opponent drop their weapon.