Green’s Dictionary of Slang

1. tough, uncompromising, incorrigible.

1960		N. Hilliard Maori Girl 252: The usual crowd were there, hard-case women and hard-shot men.
1968		G. Slatter Pagan Game (1969) 231: He was the hard shot boy of the town. But all was forgiven when he became an All Black.

2. of a woman, sexually available.

1992

A. Duff One Night Out Stealing 17: Oh boss! it’s only a lit ole fight. Men, as well as the hardshot women only to be found here.