I wrote a little form letter to send to people haveing this problem. I'll just copy it over here, so all can read and understand his little feature about LBT molds.
Almost always, oversize bullets like you have are due to not closing the mold tight DURING the cast. With the sprue plate open, try closing the mold tight and releasing pressure off the handles while looking between the blocks at a strong light. If you can't close it till there is no light, look for a speck of dirt between the blocks, or be sure the pins are lubed with the supplied mold lube. If it springs back open when pressure is released, just be sure to hold firm pressure on the handles DURING the cast. The mold will break in and close easily without springing open after a few hundred casts. I make my molds with very tight pins, and set them about ten times deeper than any other moldmaker, so they will last a lifetime without going out of round. So I have to train customers on how to break them in fairly often. If this procedure doesn't fix your problem, or if you have further questions, write again, and if necessary you can return it for replacement or for me to fix.
Veral
