 They estimate that 10% of bone fractures in the data may be the result of indirect injuries, that is, bones fractured by the bullet passing close to the bone without a direct impact.A Chinese experiment is cited which provides a formula estimating how pressure magnitude decreases with distance.Together with the difference between strength of human bones and strength of the animal bones in the Chinese experiment, Bellamy and Zajtchuck use this formula to estimate that assault rifle rounds "passing within a centimeter of a long bone might very well be capable of causing an indirect fracture."