Seven Blades in Black by Sam Sykes

Sal the Cacophony is a gunslinging wizard-hunter on a mission of vengeance, and—armed with a giant sentient handgun—she’s on the hunt for seven vicious outlaw magicians. This book is brutal and bloody with big battles and lots of action, but also features rich, inventive worldbuilding, snappy dialogue, and characters with surprising humor and heart. I couldn’t put it down! - Stuart