sew classic has the correct bobbins
places here in town sell "301" bobbins and they are a joke...they have slots or the post part is 1/8 inch to tall - a real zoo out there.....one LQS had orderded some from a country (name starts with 'C') and they are so obviously wrong that they are making earrings and charm bracelets from them. LOL
My SINGER 301A is my favorite also...but I can only say this out loud because the Bernina 1630 is visiting my DD and the serger has its cover on.