 Tissue behaves similarly enough to water that a sonic pressure wave can be created by a bullet impact, generating pressures in excess of .Duncan MacPherson, a former member of the International Wound Ballistics Association and author of the book, Bullet Penetration, claimed that shock waves cannot result from bullet impacts with tissue.In contrast, Brad Sturtevant, a leading researcher in shock wave physics at Caltech for many decades, found that shock waves can result from handgun bullet impacts in tissue.