I can say that the marlin 780 series of .22cal rifles were discontinued in 1988.Maybe the Marlin Firearms company wb site may be more helpful?
With the serial number that you have supplied,your Marlin model 780 was made in the year 1978.
Your Marlin model 780 was made in the year 1987.
Your Marlin model 780 was produced in the year 1977.
Your Marlin model 780 was made in the year 1977 with the serial number that you have provided.
1982
1986
1985.
The first two numbers of the given serial number indicate the year the gun was manufactured. In this case, the gun was made in 1979.
In 1980 the serial #s for the model 780 ran from 20,690,001 to 20,815,000. looks like a 1980 model to me. answer by catfishiowa
The Marlin 780 dosent use a clip, it uses a magazine. You can get these from aimsurplus.com
I have seen a few of these come through my shop. I have come to learn that in the late 1970's through the mid 1980's you gun was manufactured for JC Pennys. It is actually a Marlin model 780, and the value would be as the same MD's Gun Repair mdsgunrepair.com
It is the Marlin trademark, they put it on all there rifles or use to, it is the Marlin bullseye.