Molds are regulated with different alloys. That alloy may be needed to get the proper diameter, as cast. Lee 10-1 Lead/tin. Lyman #2. Saeco - Taracorp’s Lawrence Magnum
bullet alloy (2% tin, 6% antimony, 1/4% arsenic,
91.75% lead).
A higher % of antimony makes bullets harder & larger in diameter.