What about all the other killers?

Cigarettes: 50 deaths a day in Australia - http://www.quitnow.gov.au/internet/quitnow/publishing.nsf/content/warnings-graph

Alcohol: 5,554 deaths and 157,132 hospitalizations in Australia in 2010.

And I know what you're probably thinking: the above two examples are voluntarily undertaken by the people doing them. That might be true, but do addicts necessarily think with logic? Their addiction drives them. People also suffer from a "that'll never happen to me" mentality.

On top of that, there are victims in the alcohol related deaths category in the form of victims of drunk drivers.

In 2015, 10,265 people died in alcohol-impaired driving crashes, accounting for nearly one-third (29%) of all traffic-related deaths in the United States.
Of the 1,132 traffic deaths among children ages 0 to 14 years in 2015, 209 (16%) involved an alcohol-impaired driver.

https://www.cdc.gov/motorvehiclesafety/impaired_driving/impaired-drv_factsheet.html

In the last 50 years, we've lost 949 people to mass shootings https://www.washingtonpost.com/graphics/national/mass-shootings-in-america/

That sucks, because those are real people with real lives. But all deaths are real people with real lives, and if psychopaths want to kill, they'll figure out ways to do it.

"Yea cos a guy in a car could injure 500+ and kill 50+ before being stopped."
https://en.wikipedia.org/wiki/2016_Nice_attack - 86 dead, 458 injured

"bombs are hard to get a hold of."
People make them, they don't stop off at Wal-Mart.
https://en.wikipedia.org/wiki/Boston_Marathon_bombing
https://en.wikipedia.org/wiki/Oklahoma_City_bombing - 168 killed
https://en.wikipedia.org/wiki/Centennial_Olympic_Park_bombing

China stabbing spree: https://www.nbcnews.com/news/world/least-27-dead-dozens-injured-china-knife-wielding-spree-n41966 - 33 dead, 130 injured

On September 11th, 2001 we lost 2,996 people and 6,000 were injured. My point: if people want to inflict mass casualties, they'll figure out a way.

If we banned guns tomorrow, would some of those 949 deaths been prevented? Probably, but this also doesn't account for the lives that guns have saved, which would have been lost and the crimes that have been stopped due to the presence of a firearm. And, undoubtedly, some of those death numbers would have shifted to a different type of death (i.e. gun related to bomb, or knife-related).

It sucks, but you're trying to fix an age old problem. Murder is illegal, but people still find a way.