It was purportedly (and probably in actuality) intended as a survival aid to be used after landings and before recovery in the Siberian wilderness, although allegedly was intended as a defensive weapon against in-space attacks by the US space program.
Yes, I guess? But firing a gun inside a spacecraft would be a bad idea… and also firing it while spacewalking would be a bad idea unless you were very sure that you were very well braced & tethered.
You could load it with very small, light, or soft pellets, they don’t need to be very damaging to make a hole in a suit which would be near certainly fatal.