NAAA(R) .22 Magnum Rimfire Mini Revolver North American ArmsA(R) Mini Revolvers are equipped with a unique safety, giving its owner maximum protection against accidental discharge. The North American Arms safety cylinder feature allows the gun to be carried fully loaded. There are halfway notches between the chambers. The hammer is lowered into one of these notches after the gun is loaded. When the hammer is pulled back to the firing position, the cylinder rotates to the next chamber.