The choice of murder weapon obviously has more to it than whether bullets are available. The US has the most guns amongst its citizenry than any other on the planet yet a large percentage of homicides there are stabbings.
Availability, ease of use, likelihood of success/failure, and ability to be detected prior to and hence defended from, and for it to be detected after the act (who wants to be caught?) would all be considerations that may make it far more viable and attractive as a method, let alone the cost - bullets may be cheap but guns aren't.
Availability, ease of use, likelihood of success/failure, and ability to be detected prior to and hence defended from, and for it to be detected after the act (who wants to be caught?) would all be considerations that may make it far more viable and attractive as a method, let alone the cost - bullets may be cheap but guns aren't.