From publisher blurb:
The pen might be mightier than the sword, but it don't hold a candle to my peace-keeper.
The Complete Gunslinger contains the definitive version of perhaps Mage Hand Press's most fun and magnetic class to date. It comes with 16 subclasses for gunslingers of every stripe and even more class variants tied to the gunslinger's setting, so you never run out of options for your character.
This master of gunplay comes packaged with an extensive list of firearms, ranging from muskets and assault rifles, to rocket launchers and futuristic blasters -- everything perfectly balanced with other options in 5th edition. If you haven't played with the Mage Hand Press firearm rules at your table, you should pick this book up for these guns alone!
Lastly, the book contains a number of options for other characters: feats and spells, so that other characters can enjoy a bit of gunslinging fun, without jumping into the gunslinger wholesale.