If the goal is to convert a fence-sitter, the black rifle might be a bit much. That's a big step - no gun to "Rambo's gun."
IMO, it's the exact mental self image projected by your poster that causes most would-be shooters to hesitate. She's not going to want others to see her as that woman, either.
Why not a descreet little LadySmith instead?
Just my $.02.