Science on blank wounds.

Blank firing pistols are generally considered to be harmless and these guns are not accepted as being firearms in most countries. Due to lack of legal regulations these guns are easily purchased by anyone aged over 18 years. Reports of serious injuries and even fatalities due to these guns are increasing in the literature. These guns when modified or even unmodified can cause serious and potentially fatal injuries. Without doing any changes to the barrel, using blank or tear gas cartridges, firing at contact range can cause penetration of gas into the body including bone originated from gun powder. We report two suicide cases shooting themselves at temporal region with a blank cartridge gun at contact range. There was no foreign body on radiological examination and there was no trajectory of a bullet inside the brain. In both cases the wound was at the right temporal region and there was defect at temporal bone. There was circular soot around this bone defect. The injury of the brain tissue was localized at the level of the defect but there was widespread subarachnoidal bleeding.
http://www.ncbi.nlm.nih.gov/pubmed/19573850

The authors describe 3 cases of lethal injuries caused by 7.62 mm blank cartridge shots from military automatic rifle of domestic origin (AK 47, 7.62 mm). In 1 case, the cartridge was fired from a weapon that had been leaned on the head, with subsequent destruction of brain, and in other 2 cases, the weapon had been leaned on the chests, which led to destruction of heart parts. The injuries were caused by the action of striking wave of gunpowder explosion, the air blast type. The cases demonstrate that the gas pressure from the exploding propellant of blank cartridge is powerful enough to penetrate the thoracic wall and the skull.
http://www.ncbi.nlm.nih.gov/pubmed/19901805

Lethal injuries of the thorax due to shots fired from blank cartridges calibre 8 mm are reported in three cases. The muzzle of the weapon was in contact with the left side of the breast (contact discharge) and injuries to bones were absent in all three cases. In two of the cases the pericardium was not involved but the anterior wall of the right heart ventricle was ruptured and death was due to cardiac tamponade. In the third case the pericardial sac and the left ventricle were both ruptured and the victim died due to rapid exsanguination. The cases demonstrate that the gas pressure from the exploding propellent of blank ammunition can be powerful enough to penetrate the thoracic wall.
http://www.ncbi.nlm.nih.gov/pubmed/9541854