I got a new Lyman 457122 Gould hollow point mold and cleaned it and started casting. I'm using a cast iron pot, 2 burner Coleman stove, a Lyman ladel, and 50/50 (ww/Pb) approximate metal. I got a number of good boolits (around 20) once it heated up, maybe five or so boolits to heat it up. My temps were up around 830 so I cooled it a little. From one great boolit to the next I had almost 1/3 incomplete fill on the base. I continued to cast and continued to get poor bases. I checked my temp and was down to 750. I thought it should cast at that temp, cleaned the top of the mold, applied BullPlate to it, and still got incomplete fillout. Finally I got one that didn't even complete the boolit, I knew I was too cold.
I upped the heat and didn't get a good boolit until I hit 817 degrees! From then on it cast fine with no problem as long as I kept it around 830. I have just never had a mold that required this much heat.
I'm using one of the Chinese electronic thermometers so my temps ought to be accurate. It is accurate for air temp.