I can't remember where we bought them but my sister and I have prewound Bottom Line bobbins that we use in our Lizzie. I have found that I have to tear off the cardboard sides. Your's my react differently, try and see. Pre wounds in a "M" size with Bottom Line last forever. They can really get a lot of thread on there. Maybe your bobbin winder needs a little adjustment. Do you have the stand alone or onboard winder. Our stand alone came with instructions for adjustments. Now that I think about it, I think we may have bought our prewounds at Kingsmen Quilting, try there.