Abstract: Tracking where a gun has come from and finding out who used it is very important when solving crimes. Normally, guns have serial numbers on the outside that help in identifying and tracing them. But sometimes, criminals damage or remove these serial numbers to hide the gun’s past. To solve this problem, a new and safer method is being used — putting secret codes inside the gun’s chamber and other hidden parts. These codes are placed in areas that are hard to reach and cannot be easily erased. This paper explains the different types of these hidden codes, such as serial numbers, microstamps, QR codes, and barcodes. It also describes the modern methods used to mark these codes inside guns, like laser engraving and microstamping. These methods help police and forensic experts find out where the gun has come from and help them solve cases faster. Although this system can help in reducing gun crimes, there are still some challenges like high costs and the need for new laws. Overall, using hidden engraved codes inside guns is a big step forward in improving gun tracing and making communities safer.
