It falls into the category of 'Ladies Purse Pistol' and the .22 ones are usually chambered for the .22 BB Cap (Bulleted Breach Cap) the smallest of the .22 rounds.
Not in the same league as the .44 Magnum but still better than nothing and as they were loaded with black powder they made a satisfying bang and flash and at point blank could hurt like hell and also could be fatal if the entry point was the eye or the ear.
Safe to fire with original loadings but make sure that the main spring is strong as it is what really holds it shut when fired.
Not a target model.
4.750" is a bit on the big side, the last one that I measured was 4.175" and 2.405" in height, didn't have a hammer though, so say 3.000" *with hammer down.
* One must be precise, you know.
Self Defence is not only a Right, it is an Obligation.