Black Powder Spectacle (Combat, Performance)Source Inner Sea Combat pg. 12 (Amazon)
You can sacrifice ammunition to make a grand spectacle.
Prerequisites: Amateur GunslingerUC or the grit class feature, base attack bonus +4.
Benefit: When you spend a swift action to attempt a performance combat check, you can sacrifice one cartridge or an amount of black powder required for a single shot to make either a loud sound or an impressive flash. If you choose to make your weapon’s report louder, you gain a +4 bonus on all Intimidate checks you attempt for 1 round. If you choose to create an impressive flash, you gain a +4 bonus on any Perform checks you attempt for 1 round.Source Weapon Master's Handbook pg. 24 (Amazon)
You can spend 2 stamina points when using Black Powder Spectacle in order to gain a +4 bonus on Intimidate checks and Perform checks for 1 round.