Subcutaneous emphysema is often found in car accident victims because of the force of the crash. Chest trauma, a major cause of subcutaneous emphysema, can cause air to enter the skin of the chest wall from the neck or lung. When the pleural membranes are punctured, as occurs in penetrating trauma of the chest, air may travel from the lung to the muscles and subcutaneous tissue of the chest wall.
Both the Army and the Marine Corps teach that the maximum effective range of the M16A2/A3/A4 is 500 meters on a point target (individual enemy) and 800 meters on an area target (i.e. troops in the open).
It is accepted that if you do your job and put the bullet where it counts, you can count on the .308 to do its job and incapacitate the target. The US Army preaches an 800 meter maximum effective range for the .308, the USMC preaches a 1000 yard (915 meter) max effective range.hile we have made hits at 1000+ meters with the .308, we tend to agree with the Army and indicate that 800 meters is about the max limit for RELIABLE hits in all but extreme weather conditions.