Not to argue via Stats (even though they're on the pro 2A side)...Between 1945, (the earliest figure available for per capita firearms, Kleck) to 2014 ( the latest figure, using BATFE numbers and Kleck's methodology), the number of per capita firearms has risen from .351 to 1.176. That is more than a three-fold increase.
During the same period, the per capita rate of fatal firearm accidents has declined from 1.84 per 100,000 to .15 per 100,000, over a 91% drop. Using the earliest number in 1933, the drop has been nearly 94%.
For my money, there's an Objective Moral Standard that is a more compelling argument.