A quick determination whether a fired cartridge case is a reloaded case or not has several practical implications for responding officers, crime scene technicians, and criminal investigators in the field. Such a determination would give them a precaution: (1) The fired case may have been be fired by one or several weapons. (2) A quick determination of reloaded and fired pistol cases should assist criminal investigation in narrowing down the type of ammunition used, the type of suspects involved, and a possible link between the reloaded case(s) and the reloading machine at the suspect's residence. (3) If the case goes to the court, the expert opinion from the examiner would be challenged heavily by the defense. Currently, little information and research is available on the topic. Based on the observational examinations of reloaded and fired pistol cartridge cases (N=100) with three types of calibers (.45, .40, and 9 mm), this study offers three practical guidelines for a quick determination of these reloaded and fired cases by naked eyes or a magnifier. These three guidelines should be relevant and useful in identifying reloaded and fired pistol cartridge cases at the scene and as reference later in comparing them in the lab to improve criminal investigations.