It occurred to me that one resource the gunslinger is going to have a lot of and little use for is his attacks of opportunity.
After all he's using ranged weapons, he has a lot of reasons to raise his Dex, but he doesn't gain any benefit from his attack of opportunity or the extra ones he could get with combat reflexes...
So why not change the cost of some (or all) of the deeds to attacks of opportunity?
This would be a refreshing resource, that can be used up to do all sorts of things and would give the gunslinger both something new, and use something everyone is already familiar with.
Examples could be:
Duck for Cover: As an immediate action give up an AoO to move 5 feet as someone is targeting you for a ranged attack. If you get behind cover you gain the benefits of cover for that attack (you do not gain the benefits of total cover though as you are moving as they shoot).
Surprise shot: If you are using a weapon with the scatter property loaded with pellets you may use it to make an AoO against anyone moving within the range of the cone.
Fast Reload: Give up an AoO as a swift action to reload one shot. You may give up extra AoO's to reload extra shots as part of the same swift action, but only to load a gun you already have in your hands.
Snap Shot: As an immediate action you may make one attack on a target within your first range increment at a -5 penalty -- using this ability uses up an AoO.
Pistol Whip: You may make AoOs with a firearm in your hand. Doing so is a melee attack that deals damage as a club for an one handed fire arm and as a heavy mace for a two handed fire arm. You may add any enhancement bonus on the gun to this attack.
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I'm sure people could think of more things to add to this list (or other abilities from the current deeds to put on it).
I just feel this would handle the 'refreshing' time of the Grit ability and use up a resource that people already know about and understand.