Good out to say 15 feet - but its definately not a precision weapon! It doesn't really have a rear sight, just a groove that goes down the spine of the frame. I don't shoot it recreationally, I just carry it for the worst case scenario kind of situation. Most gun fights happen within 8 feet or something though - and are only 3-4 shots (something like that). You're definately compromising your capacity with the 5 shots in that 642 - but you can be worry free about jamming and some other problems that can happen with autos (or coming out of battery when you've got it jammed in someone's gut, or not cycling a 2nd round in that same situation because of clothing getting stuck in the slide)

My baby Glock 26 is very accurate, I shoot as well with it as I do with a full size Glock - but its not going to work in your pocket very well (I carry it IWB or ankle very easily though).