I agree with "a deadly weapon is a deadly weapon" but I also see the OP's point. I have to believe that it would be considered on a case by case situation and also depend upon the make up of a jury.
Case in point - several years ago in Michigan, police responded to a alarm at a bank in the early hours of the morning (I'll try to remember the facts the best I can) - I believe around 3 a.m. A number of officers entered the premises and cornered a girl inside who was also high on drugs. They finally subdued her on the floor and in the process of trying to cuff her, she broke loose and had a utility type razor knife which she tried to slice an officer with - mind you, if she had hit his carotid artery in the close quarters they were in with her - the officer could have been killed or maimed for life. As a result, an officer drew his weapon and shot her - with the result of her death. If I remember right, it was ruled a clean and justified shooting by the DA. However - since she was a minority - it soon became blown out of proportion with even a preacher (I believe he was from a church in Lansing) who started making charges that it was an unjustified shooting - excessive force - played the minority card, etc.
Yes, the shootings are unfortunate and we all feel sad about them - but in the end, it wasn't the guns that killed - it was the individual behind them. I won't even get started on that. My point is - if someone attacks you and intends to do you great bodily harm and you fear for your life - it matters little if they are armed with a gun, a knife, a lug wrench, a ball bat or even an automobile - the end results are the same - you could end up dead. Yes, it would be nice if there was a LE officer right there to handle it so you wouldn't have to - but the chances of that are pretty bill. (This is not meant as a criticism of LE.) Unfortunately - they will eventually get involved in the situation - after the fact when they have to sort out what happened - and by then, it's too late for you unless you come out on top.
If a pair of '51 Navies were good enough for Billy Hickok, then a single Navy on my right hip is good enough for me . . . besides . . . I'm probably only half as good as he was anyways. Hiram's Rangers Badge #63