Expertise Feats

Firearm Expertise

Benefit: You gain a +1 feat bonus to weapon attack rolls you make with a firearm. This bonus increases to +2 at 11th level and +3 at 21st level.

Also, you reduce the time it takes to reload a firearm by one step. So a musket would only require a minor action to reload, and a pistol or revolver would be a free action. This feat stacks with the Speed Loader feat, allowing you to reload a musket as a free action.