There was never a "gunslinger" law... that's what people called it, but it was never a codified law called the "gunslinger" law.
By the way, open carry, by definition, is legal in MS. However, our AG's have destroyed what 'conceal' means, and basically anything that you carry in a holster, they consider concealed.
I'm writing a firearms law primer (pun intended!) that I'm going to get published next semester. I have a *very* notable attorney that is overseeing me.
I'll post it when I'm finished with it.