Instructions
Unload the gun and make sure the safety is on, since you will be handling and manipulating the gun.
Examine the gun. The location of the serial number will vary based on the make and model of the gun. Check the butt of the gun, the frame and under the barrel. Bring your firearm to a gun shop if you are having trouble locating the serial number.
Read the documentation that is supplied with the gun. The serial number is typically listed; again, the location will vary based on the make and model of the gun.
Check the invoice. The serial number likely will be included. The location will vary based on the manufacturer.
Contact the manufacturer to receive guidance in finding the gun's serial number.