Using a digital thermometer & thermocouple probe placed in the bullet cavity & with the mould setting on a hotplate, I’ve determined that the ideal starting temperature for my BACO 409400M4 .40 caliber single cavity cast iron mould should be around 575 degrees F. At that temp the 1st bullet that drops out of the mould is within 0.5gr of all the rest. At 500 degrees it requires 4 or 5 bullets to bring the mould up to the correct temperature, at 450 degrees 10 to 15 bullets are required. Of course a cold mould would require more.
BTW, I’m casting the 400gr bullet at 765 degrees with 16:1 alloy & using a PID controller. I do not monitor the mould temp while casting.
Wayne
Last edited by texasmac; 12/15/17.
