...I disagree.
You are trying to claim that people who would have killed with firearms but were unable to do so due to no access, would simply kill with some other weapon. IMO, this is completely untrue, but for argument's sake, lets try running with that.
If your claim is correct, it would mean that in countries other than the US (those with actual gun control and a lower rate of firearms ownership) the overall murder rate (say, per 100,000) would be the same as the US, and the rate of firearms murders will be much lower, so the rate of murders with other weapons would be much higher to make up the difference. This is simply untrue.
Comparing the base rate of homicides of the US to any other country is apples and oranges. It's is an unfair comparison because that comparison ignores a vast amount of other variables that contribute to the homicide rate that you did not control for. In recent history, the US has had a higher rate of homicides than other developed nations. There are many reasons for that higher rate, and the vast majority of them are unrelated to firearms.
The question poised is if Australia's ban on semi-automatic firearms changed the downward trend of homicides before the law was implemented. The answer is inconclusive. You can find research that says yes. You can find research that says no. The reason for this is because the availability of firearms is NOT a good indicator of the homicide rate. If the intent is to save lives, banning firearms is not an effective method to achieving that goal.
Additionally, I wonder how many people the Las Vegas spree-shooter would have killed and wounded using a knife, or a baseball bat from his hotel room. I wonder now many he would have killed if he was only able to get single shot, bolt action rifles with a maximum of 10 round per magazines.
If we are to hold all variables the same, and assume that absent any semi-auto weapons, I agree that the Las Vegas shooting would have resulted in less deaths. However, holding all of the variables constant is not how the world works. We do not exist in a vacuum. The Las Vegas killer could have done a variety of things which would have still resulted in a similar death toll. He could have created a bomb, he could have drove a car into the crowd, he could have searched for semi-autos on the black market (Which interestingly enough, Australia's firearms black market is booming). Further more, homicides classified as mass shootings are such a small percent of all homicides that reducing them by 20, 30, or 40% would not have any? statistical or a very small statistical impact on the overall homicide rate.
Did you know that Australia has had 6 mass shootings since the 1996 semi-auto ban? I wonder what happened to accurate reporting?
Again, I state that I do not believe that categorizing mass shootings, while ignoring mass killings is an honest method to studying the effectiveness of firearm bans. If guns become less prevalent, it make sense that killings with guns would become less frequent. The question is have you actually saved lives or shifted those mass killings to another method?
I acknowledge that Australia had 10-ish mass shootings during the 20 years before the semi-auto ban, and a reduced amount of mass shootings after said law was passed. During the same time period, New Zealand also had a decline in mass shootings without reducing its availability of guns. More evidence that the availability of firearms is not a good indicator of the overall homicide rate.
The availability of firearms in the US has grown substantially in the last 20 years, yet the homicide rate has decreased. More evidence that the availability of firearms is not a good indicator of the homicide rate.
I'd say you were making a strawman argument. A red car is still a car, and other than colour, it is exactly the same as any other car
A firearm is NOT the same as a knife or a weapon other than a firearm
Your comparison is just nonsense.
A strawman is an attempt to refute your argument by making framing your argument I create and then refuting the argument I made. That is not what I attempted. I attempted an analogy. If you cannot see the error of celebrating the success that banning guns results in a decrease of homicides committed with guns, while examining how the homicide rate regardless of instrument changed, then we have nothing further to discuss.