Gunshot Residue (IMAGE) American Chemical Society Caption With what could be a shot in the arm for crime scene investigators, chemists have developed a reliable new test for detecting the presence of gun shot residue. Above is a residue particle -- roughly 1/20 the size of a period -- that has been magnified 200 times with a digital microscope. Credit Courtesy of Garrett Burleson Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.