I adore my '64!
Iff you can post a pic of your rifle, it will be much easier to get some help. As Mr. Toymaker (worth reading his stuff!!!) suggested, there are 2 different Sears .22's called a 6c. If your's is a '64 copy, parts are readily available through Savage and, in the EE.
I'm not as familiar with the Winchester but, can't imagine them too hard to find parts for.