Here are several advantages that a small-frame revolver holds over an autoloader for deep concealment:
Due to the shape of the rounded grip profile, a revolver that rides close to the belt line for maximum concealment offers a better grip than does an autoloader. The front strap of an auto rides directly on top of, or even buried slightly below, the belt line or pant line if worn in a belly band or other means of deep concealment that sits the gun low on the waistline for maximum concealment. Therefore, all things being equal, the revolver offers a better grip from such a carry mode.
Another notable advantage that a revolver offers for such concealment modes is the fact that the gun has no tang. The back of the slide and rear sight often print quite conspicuously on an autoloader if worn under tucked-in shirts. This issue is entirely absent on a revolver.
The grip itself, even if not necessarily smaller than that of a diminutive autoloader, is rounded in a more organic sort of shape. Rather than a contrasting blocky shape as found on an auto, the revolver grip has a rounded and organic looking outline when pressed against the body, thus concealing better.
And, yet another significant advantage concerning deep concealment carry, the weight of the revolver is in the cylinder, which rides below the belt line. One challenge with concealing an auto in a belly band or other concealment where the retention is not provided by a stiff belt is that the grip tips out and away from the body and prints more. This is because most of the gun’s weight is in the grip. A revolver is less prone to this due to the weight being in the cylinder which rides below the belt line.
I have used a Ruger LCR for many years for my deep concealment needs, but of late I have been wearing my Glock 26 in such deep concealment modes. The truth is, the Glock 26, even with a 12 round Magpul magazine, hides quite well. However, the revolver still hides better under tucked shirts, and the Glock proves more difficult to grip and draw from this carry mode.
Therefore, I am back to the LCR for such carry purposes. While the Glock 26 is, obviously, the more capable fighting gun, being able to quickly, and efficiently, deploy the tool is top priority. Defensive guns are purpose driven tools. I still find that small-frame revolvers serve for deep concealment carry better than anything else.