What kind of title is this?: Manga.
How many volumes are there?: 18 volumes are listed.
How many chapters are there?: 78 chapters are listed.
Where can I read it?: Reading links are listed for Yen Press, Official Site. Check availability in your region.

Synopsis

About Aoharu X Machinegun

Hotaru Tachibana is a girl (though all too frequently mistaken for a boy!) with a deep sense of justice. When a classmate informs Hotaru that she was bilked out of her cash by a shady host at a host club, Hotaru immediately rushes to confront the villain only to discover that the con man in question is her new neighbor! Worse, he proposes to settle their feud with firearms! Okay, it turns out that they're just toys, but when Hotaru is soundly defeated, she finds herself sucked into the world of survival games. Is this new world one she can actually escape?? (Source: Yen Press)

Action Comedy Slice of Life Sports