Marlin is a popular gun manufacturer brand in the United States. The .30-30 is a type of small-bore, sporting rifle cartridge found in many Marlin hunting rifles. Rifles that are chambered in .30-30 include the Marlin 336A and 336C model numbers. Each Marlin rifle is engraved with a unique serial number that can be used to trace its ownership. The location of the serial number varies with the age of the rifle.
Write to Marlin with information about your rifle, including model, serial number, caliber, and barrel markings. Marlin will furnish general information to you about the model. Marlin's address is: Marlin Firearms, P.O. Box 1871, Madison, NC 27025.
Check the bottom part of the tang, or sight, under the level.
Look for the serial number on the top tang behind the hammer.
Check the back of the hammer for the serial number.