I have a gunslinger in my campaign. I'm running Armor as Damage Reduction optional rules. This sort of screws the gunslinger. A lot. It effectively takes away the primary reason to wield a gun in the first place. He's upset because he says that he could be a stronger character by picking up a longbow instead of using his gun. As far as I can tell, he's not exaggerating.
We are currently level 3, but will probably make it to 15 or so. I'd appreciate some help. Probably in the form of a feat or ability to suggest. The sooner he can get it the better.
You don't need a feat. Just have Armor Piercing bullets. As GM you can control the ammunition availability or difficulty of crafting, so that it doesn't become a game breaker for you.
IRL, I don't need a new "feat" or better skills to punch through heavier protection. Sometimes I don't even need a new gun. Just switching ammo can do it.
Gunslingers can have a rough time until level 5. Once they start adding Dex to damage though I have trouble seeing how a longbow is going to be stronger in most circumstances.
If it's the damage reduction as such that's bothering him, tell him about Clustered Shots. Yes, it'll only help from lvl 6, but as said, gunslingers really starts picking up speed at lvl 5 and beyond.
If he's bothered about his 'targetting touch AC' aattacks not being as cool when people are not really using AC, then I can't really think of anything to console him. :)