I bought & carried a tiny North American Arms .22 rimfire revolver right after they came out a good many years ago. This was before NAA wisely added the indentations between the chambers on the rear of the cylinder in which to rest the hammer.
I understand that North American Arms will exchange cylinders with owners like me who have the old style cylinders, but since I rarely carry the mini-gun anymore, it isn't worth the trouble to send it back to the factory to have that done.
As a result, my NAAs mini-revolver does NOT have the small indentations between the chambers. It is single-action only... and is obviously meant as a VERY close range, last-ditch, self-defense revolver.
For safety's sake, I loaded only 4 rounds rather than the 5 rounds the tiny cylinder will hold and left the hammer down on an empty chamber when I carried the tiny revolver.
The standard NAA's .22 rimfire revolver is considerably smaller & lighter than the .22 magnum model... and is definitely a "belly-gun". If used only at very short range (10-15 feet or less), it can be an effective self-defense gun. I found it to be reasonably accurate as well as long as I put my shooting hand's thumb on top of the little revolver's frame when I fired it.
This usually resulted in getting some slight powder burns on my thumb... but they didn't seriously hurt... and doing so made the little revolver considerably more accurate.
Like the single action revolvers of old, one should not carry an older model like mine with the hammer resting "down" on a loaded chamber since the firing pin (the front of the hammer) will be resting on a loaded cartridge... and a hard "bump" against the hammer spur could fire the cartridge.
Another safety consideration is that one should NOT carry any hard objects (like coins, pocket knives, etc.) in the same pocket with the minature revolver because the rear of the cartridges in the chambers are exposed and, if somehow struck by a hard object, it is possible the round might fire... possibly resulting in serious injury or even death.
Soon after Kel-Tec announced their P3AT (.380 ACP), I bought one to replace the little North American Arm's .22 rimfire long rifle mini-revolver I carried that I loaded with hyper-velocity .22 rimfire hollow-points.
Naturally, the little NAA .22 mini-revolver is smaller and more concealable than the small Kel-Tec .380, but the Kel-Tec's .380 rounds are considerably more powerful and the Kel-Tec carries a total of 7 rounds... 6 rounds in the clip plus one round in the chamber and is also VERY concealable. As a result, since I got the Kel-Tec, I stopped carrying the mini-revolver.
Some of my friends have jokingly teased me about the small pistols I carry... but I tell them that I'm not out to start a "war" with either the North American Arms mini-revolver OR the Kel-Tec .380 ACP.
I point out that I had to pull out the the little NAA's mini-revolver only once... to stop an unwarranted attack by a bigger, younger aggressor... and when the goblin found himself looking down the "business end" of the little .22's barrel with the other gleaming hollow points "looking" at him from their cylinder holes, he decided that "discretion" WAS the better part of valor... and wisely stopped his attack IMMEDIATELY.
In that short moment, the total purchase price of the mini-revolver became fully justified.
Strength & Honor...
Ron T.