McDaniel preferred to use copper-coated BBs, which sparkled in the sunlight, and he selected safe shooting locations that were not ringed with tall trees so that when looking up, the student would see only the thrown aerial-target and the fired BB against a background of the open sky. The objective was to make it as easy as possible for the student to track the path of the fired BB through the air in relation to the target. (McDaniel always insisted that the student wear sunglasses or safety goggles, in case a BB ricocheted off a target and hit the student in the face—as occasionally happened.)