how to get the most damage with a far reaching sight PFS?

[Sonea Evareska]

I cant say how much i love the concept of playing a ranged sniper making that one shot that can change the flow of battle. and since finding out about the gunslinger class, i've been having a lot of fun playing the part.

E.g.

segang expedition:

The part where you climb up in your hunter blinds to take out the beast where we spread out to make sure we catch it. The cat turns out to be magical and uses a charm to lure the NPC you're escorting and proceeds to maul him badly. It was dark so no one can see what was happening, until one of the group gets close enough to see the cat. By the time he got close enough to actually see what was happening, the NPC was down and bleeding on the ground.

My turn was up before the beast again. I had only 1 option at that point, load a flare cartridge and try to blind the creature. I burned my grit for deadeye, made my hit to concealment roll (called high is a miss, rolled a 50) , and gm failed the save. The cat was BLIND! Glad to say high fives were given all around. This gave us the chance to save the chief and take care of the beast.

Anyway back on topic, I saw this nice piece of equipment for moments like that when I need to make 1 shot.

Far reaching sight
This sight can be attached to a single two-handed firearm. When this is done, the sight becomes part of the weapon, but can be removed from that weapon with a full-round action. A firearm wielder can choose to spend a full-round action to make a single shot with a firearm that has this sight. When she does, she can resolve the attack against the touch AC of her target regardless of the range increment.

What I'd like help with is what can I do to up the damage for this shot? Deadly aim is a given, while I think Vital strike doesnt work since it specifies attack actions, while the sight works as a full round action.

[Secret Wizard]

Might want to multi class to boost that damage. Guide Ranger or Urban Barbarian (Savage Technologist doesn't overlap well) come to mind as classes with many one shot wonder abilities (remember Urban Barbarian can take the Surprise Accuracy rage power line).

Yet another option is a Bard or a Spell Warrior Skald. Besides a damage boosting performance, it grants you access to Arcane Strike or, even better, Timely Inspiration, which you can use as an immediate action to make sure your long shot hits. But you do lose BAB.

[Claxon]

Practically speaking you're just asking to increase the damage of a weapon. It's not something that really depends on or is affected by the use of the far reaching sight. Further, as a full BAB class your chance to hit a target with your first attack is probably high enough that you don't need to worry about needing to target touch AC, you'll hit them regardless.

It's also questionable whether or not the touch attack granted by the far sight scope would prevent the use of deadly aim or not.

Ultimately, ranged attacks don't usually wallop an enemy. They usually deal a medium amount of damage per hit. The benefit of ranged attacks is making a full attack every round, and having multiple attacks.

I don't have any particularly good advice for how to maximize your damage on a single attack besides using as high an enhancement bonus to damage as you can and adding deadly aim if you're allowed. Any other bonuses to damage are probably going to require you to multiclass to obtain.