Safety glasses as protection against shotgun pellets

I designed this experiment to determine if spectacle lenses would protect against a No. 6 shot fired from a 12-gauge shotgun over progressively longer testing distances, and compared plastics, heat-tempered glass, and chemical-tempered glass lenses of standard and industrial thicknesses. The likelihood of a spectacle lens being hit by a well-centered shot pattern at 40, 50, and 60 yards was approximately 66%, 25%, and 20%, respectively. Virtually all lenses were destroyed at a testing distance of 30 yards. At 40 yards, standard-thickness plastic and heat-tempered lenses were destroyed but the chemical-tempered lenses offered some protection. At 40 yards, all types of industrial-thickness lenses provided protection but the most protection was provided by the chemical-tempered lenses. At 50 yards, chemical-tempered lenses offered more protection than either plastic or heat-tempered lenses. Throughout the experiment, plastic lenses performed no better than heat-tempered lenses.