The foot pressure matter entered my thoughts as I was reading this--If that little knob (or twister thing on the left side of your machine, kinda to the back), I don't have a 301 here in front of me to say specifically, but if it is way high, you don't have any pressure on your presser foot. And you won't have a zig zag foot on a 301, will you? It is a straight stitch only machine--but a l/4" foot comes to mind here--it is a little wider than a SS foot. Check that out. My favorite piecing machine is a 301 or FW, and I can't think of any problem I have ever had with the fabric moving evenly. Good luck, and happier piecing as your get to the bottom of this little headache.