A .38 special will do the job. You don't have much margin, but that is the price you pay for something small and easy to carry.
Every now and then the subject of CCW comes up at work, and often some guy will describe an absolutely wonderful rail equipped custom double stack etc etc etc as his carry gun.
"Man that sure sounds like a great gun, may I see it?"
"Uh..........er...........h'mm, lemme run out to the truck and get it."
By then someone in the office will have produced a Kel-Tec or an Airweight.
"What's with the silly little pop gun?"
"That's what keeps you from getting to your truck."
If a gunfight is on the schedule, and I HAVE to be there, I'd just as soon show up with an M256 120mm tank gun and riding in an Abrams. Otherwise, I carry what season, clothing, and political climate will allow.