I figure that some here are shooters/hunters and may have an interest in this article from NY Times which describes how gun blast pressure can cause Traumatic Brian Injury (TBI). This is a share, but I cannot guarantee it will work
www.nytimes.com
How Gun Blasts From Indoor Shooting May Cause Brain Injuries
The Times tested the blast waves of several popular civilian guns at an indoor range and found that repeated firing could add up to potentially harmful exposure.