Colonel Whelen takes us back to the days of World War II, when the only round that mattered was the .30-06. He goes into the weeds of the history and types if small arms, the intricacies and variations in chamber design and barrel-making; and more importantly the design of ammunition. There is no math involved, just trends he saw over his lifetime. Thus is a must-read for anyone interested in the details of firearms and ammunition design without having to break out the calculator.