The records and interviews show in stark detail the unique mechanics that propel these bullets — and why they unleash such devastation in the body. Loading This is a .223-caliber-sized round ...

223 caliber ammunition—a high-velocity, military-standard rifle ammunition often used in AR-15-style rifles—and a handgun ammunition magazine to a first-time customer, Platkin said.

Phil Massaro tackles the 6mm ARC, a military cartridge that's equally at home in the hunting field.