How did people commit mass murder before (semi)automatic weapons? With fire, typically, but there are so many options:
According to data compiled by Grant Duwe of the Minnesota Department of Corrections, guns killed an average of 4.92 victims per mass murder in the United States during the 20th century, just edging out knives, blunt objects, and bare hands, which killed 4.52 people per incident. Fire killed 6.82 people per mass murder, while explosives far outpaced the other options at 20.82. Of the 25 deadliest mass murders in the 20th century, only 52 percent involved guns.