Anything bigger than a .25 is hard to hide, dressed the way most people dress around here: slacks or jeans or shorts, shortsleeved shirt, most of the year, due to the heat.
Some years ago, and this was years before concealed carry permits were available, I was walking through the French Quarter, and noticed that the a guy about 10 paces in front of me was wearing a windbreaker: this on a day when the temperature was around 100 (we still use Fahrenheit in the States).
My first and only thought was, "that guy's carrying a gun".
About 20 paces further, and the guy raised his arms and shoulders. Up went the back of his jacket, just for a fraction of a second.
In a small of the back, inside the pants holster, he had a Walther PPK.
I don't know if he was a cop, crook, or private citizen carrying illegally, but I made a sharp right turn at the next corner.
Jim