Magazine clip for a marlin model 80 - Optics

Could need a new spring in the magazine tube.
Ebay has complete inner magazine tubes.
search for Marlin Model 60 .22 Inner Magazine Tube

Have you tried contacting a local gun show?

There are several gun parts companies that who deal in old/obsolete parts two come to mind, Brownells has many parts for both new and old firearms and Poppert's Gun Parts. Both have online catalogs and search engines. Also GOOGLE "Marlin model 80E parts" for other sources. Lastly, start going to gun shows and asking the venders if they have the magazine or a lead to find it.

Unfortunately, Ramline stopped making the model 70 mag due to the Clinton Gun Ban of 1994.

They're out there, but you have to look for them.
Either used, or NOS (New Old Stock)

Try Ebay

http://www.gunauction.com/buy/10779099/magazine-clips/ramline-banana-mag-for-marlin-papoose-or-model-70

http://www.firearmstalk.com/forums/f53/ramline-marlin-m-70-papoose-25rd-22lr-mag-38598/

Try not filling it all the way. sounds as if some debris may have gotten into your magazine tube.