In my mind the real issue is whether the shear number of weapons (guns) is a significant factor in increasing gun-related deaths.

If the number of guns per capita is NOT the problem, as Republicans and the NRA would have you believe, then why not have everyone bear an arm? Heck, we might as well make it mandatory for everyone to bear arms.   Not just teachers, but also nurses and doctors, and bank clerks, and shop owners, and cashiers at the local food market, etc. The insanity of this approach is apparent (to most of us)! The omnipresence of guns leads to accidents and suicides. People are not infallible. They make mistakes.

So what is the data that overall numbers of guns results in higher rates of gun-related deaths? It is difficult to tease this out because there are many factors that contribute to gun-related deaths. Obviously, a country like Yemen, presently in a civil war, will have a higher rate of gun-related deaths. So researchers have limited their analysis to “advanced countries” according to the human development index. The following chart lists homocides by firearm per million people:

Chart I from: https://www.vox.com/policy-and-politics/2018/2/21/17028930/gun-violence-us-statistics-charts

The US is obviously a pretty violent country. Notice Australia on the far left of the graph.

Now how does this correlate with the number of guns? This chart, from researcher Josh Tewksbury, shows the correlation between the number of guns and gun deaths among wealthier nations:

Chart II From: https://www.vox.com/policy-and-politics/2018/2/21/17028930/gun-violence-us-statistics-charts

It is pretty clear that the higher the number of guns/100 people, the higher the gun related deaths. Notice Australia, down in the left lower quadrant.  Of course there are confounding factors which these researchers carefully considered (war, poverty, slums, and social upheaval all contribute to gun-related deaths).

It is easy to imagine that fewer cars would lead to fewer car-accident related deaths. Why would that not apply to guns?

If we agree that the data suggest that increased numbers of guns per 100 people, are correlated with increased gun related deaths, ask yourselves what would prove causality. Well, there is an existing social experiment. A country that changed its laws and decreased its arsenal of guns! And the results were stunning.

The story is well described in Fortune. In 1996, a 28-year-old man drove to a popular tourist spot in Port Arthur, Tasmania, and opened fire with a semi-automatic weapon. Before the day was through, he had shot dead 35 people and wounded 18 others. With the weapons he carried—the AR-15 and a second, self-loading military-style rifle—aim was almost immaterial. He could fire multiple shots in seconds with little recoil. Pointing the gun at a crowd of tourists, it was hard not to hit somebody.

Within weeks of that tragedy, elected officials in each of Australia’s six states and two mainland territories—pressed forward by police chiefs across the continent and by the then-newly elected prime minister—banned semi-automatic and other military-style weapons across the country. The federal government of Australia prohibited their import, and lawmakers introduced a generous nationwide gun buyback program.

Australia is a land of roughneck pioneers and outback settlers. Australia had never embraced much government regulation. This was the home of Crocodile Dundee. But there had been too many deadly shooting sprees and Australians were clearly sick of them.

In 2014, the latest year for which final statistics are available, Australia’s murder rate fell to less than 1 killing per 100,000 people (see Table I).

Remarkably, gun suicides in Australia dropped by some 70 percent, according to one analysis. What stopped many of those would-be suicides was the lack of access to a gun.

It is clear in my mind: more guns means more gun-related deaths.