Well, I suppose it all depends on what type of crime is being committed too.
Domestic violence, burglary, bank robbery, arson, etc.

I was mainly using the rape scenario because it's been coming up in the news a lot and it's a scenario where using weapons would be more acceptable than something like bank robbery.
Bank robberies rarely cause fatalities because everything is insured and the money is not yours to defend against an armed bod.
Domestic violence is between family, so a call to the police will solve that dispute.
Defending against an arsonist to protect property doesn't really happen often as far as I know due to the arsonist would plan out when to do it etc. Arson involving fire is a very hard case to solve as well.

Gun prohibition well, I agree that a restriction would have a small effect on reducing gun violence (not a large percentage though due to the criminal knows about the gun laws and wouldn't care for it).