What is the best selling 22 caliber rifle of all time?

This is hard to answer, since there are several makers of VERY popular 22s, and they do not always compare records with each other. Two that would be likely contenders for that honor are the Marlin 39 series of lever action rifles, and the Ruger 10-22. While the 10-22 is a HUGE seller, the Marlin 39 series has been in production for over 100 years.