We live in a golden age that far surpasses all previous golden ages. Some call it the Industrial Revolution. Some say it is the digital revolution. This correspondent refers to it as the petroleum age.The cost of firearms and ammunition, in terms of labor, is near an all-time low. .22 Long Rifle cartridges can be had for under six cents a round, with free shipping, on the Internet. The all-time low, in constant dollars, would be about five cents per round, not including sales and seconds, from 1993 to 2006. Nominal prices are higher, but costs in labor are much...