Black Tiger

The "intense gun action" story is set in the United States in the aftermath of the American Civil War.
In the chaotic atmosphere of the postwar period, the northern government issues "Licenses to Kill"
to bounty hunters in order for them to take out the South's remaining soldiers and outlaws.
The most feared hunter turns out to be a female gunslinger known as "Black Tiger":
her determination to annihilate any kind of enemies makes her notorious both in and out of the USA.