This specific measurement refers to the cartridge case used in a widely recognized intermediate rifle cartridge. The designation indicates a bullet diameter of 7.62 millimeters and a case length of 39 millimeters. Understanding these measurements is fundamental for handloading ammunition, ensuring proper chambering in firearms, and analyzing ballistic performance.
Accurate specifications are crucial for safe and reliable firearm operation. Variations outside established tolerances can lead to malfunctions, decreased accuracy, and potentially dangerous situations. Historically, this cartridge gained prominence in the mid-20th century and remains significant globally. Its widespread adoption stems from a balance of power, controllability, and portability in military and civilian applications.