Results of experiments

Dr. Y's group performed experiments, using baby pigs under anesthesia as the target, to characterize the maximal depth and length of graze wound which can be produced by a lead bullet of the same size and shape as in the March 19 shooting. The reason to use baby pigs, between 5 kg and 10 kg, is that among domestic animals, their abdominal skin and wall is closest to adult human abdominal tissues in mechanical and thermal properties.⁵⁵

Dr. Y introduced a notion of striking offset, defined as the distance, measured along the normal direction at the peak of the target surface (abdomen of baby pigs), between the striking location and the peak of the target. The results of Dr. Y's group indicate that, when the striking offset is equal or greater than a specific value, the threshold offset, the bullet will enter the abdomen, producing a two-hole penetration instead of a graze wound. When the striking offset is smaller than the threshold offset, the bullet will produce a graze wound.

The measured value of the threshold offset by Dr. Y's group was 0.5 cm. The maximal depth of graze wound produced in experiments by Dr. Y's group was 0.26 cm.

The maximal length of continuous graze wound⁵⁶Dr. Y's group was able to produce, on the abdomen of rabbits and baby pigs, was 3 cm.

Summary The depth of Chen's graze wound, 1-2 cm, is at least 4 times the reproducible depth in the experiments by Dr. Y's group. The length of Chen's graze wound is at least 3 times the reproducible length.