The firepower available to Americans is frightening

‘How many times have we read of attacks that ended only when the shooter ran out of bullets’

It’s a familiar, wearying pattern. Another day, another mass shooting, another call for tighter gun control that goes nowhere, even as campaigners say such atrocities are becoming more frequent.

Yet criminologists are far from agreed that such atrocities are really on the rise. For every study that shows a surge in mass killings – such as the graph from Mother Jones, right – there is another, using different definitions (such as variations in the number of victims which might be classed as a “mass shooting”) and different methodologies, that concludes the rate has stayed the same over decades.

Grant Duwe, an expert on mass murder and the research director for the Minnesota Department of Corrections, for example, factored in population growth and found that the number of attacks per capita had remained at about the same level as the 1980s and 1990s.

But he found that the number of people shot is now at a 40-year high, when adjusted for a rising population. Using a five-year rolling average to calculate the rate per 100 million Americans, he notes that it remained below 20 before 2012 but has been above that ever since.

This is where the studies coincide. The attacks have become more deadly in the past decade.

Therein lies a clue to factors behind the awful death toll. The firepower available to ordinary Americans, with only basic checks, has intensified rapidly since Bill Clinton’s ban on assault weapons expired in 2004.

The ban was far from perfect. It did not apply to all semi-automatic weapons but perhaps its most important impact was to ban highcapacity magazines, which multiply the deadly impact of any weapon.

How many times have we read about attacks that ended only when the shooter ran out of bullets or was shot by police as he tried to reload?

Among the weapons it banned was the AR-15.

The National Rifle Association says it is “America’s most popular rifle”, a favourite of hunters, but its design mimics the M-16 rifle, used by American service members, making it the first choice for angry men with a grudge and a thirst for blood.

Whether that is because of its efficacy or a copycat mentality among gunmen is a constant debate. But there is no doubt that the frightening firepower available to ordinary Americans off the shelf since the assault weapons ban expired is to blame for the spiralling casualty numbers.