I had a previous topic on my issue that seems to have been deleted. There, I was discussing how I could not get my Saeco #740 mold (casts a .410" dia., 409 gr bullet) to fill out completely on one side. The bands here where rounded and not real sharp.
I had tried everything to get this mold to cast properly (it always required casting at least 30 bullets before the bullets would fill out completely and this was after the mold heated up by sitting on top of the furnace or heated with a torch). Even while casting, slight breezes seemed to cool one side of the mold. I thought I had a contamination issue, vent lines not wide enough, bevel at the top not sufficient, too low a temp, etc. You name it.
I had all but given up when I thought that I'll crank the temp all the way up on the furnace that I use for this mold (24/1 alloy), or ~825 F, and try and cast as fast as I could when the mold appeared to be sufficiently heated. I would cut the sprue the moment it solidified and also not hold the ladle to the mold any longer than enough time for the lead to run into it. Clear the mold and refill as fast as possible. Low and behold the bullets started filling out completely!
I normally wait a few seconds after the sprue solidifies and hold the ladle to the mold for a few seconds too with my other molds, but this mold like to be real hot.
I have now switched alloys between my two pots and the Lyman one, which I will now use for this mold, can reach 1,000 F! I'll probably cast at 875 or 900 F with this mold in the future. My RCBS pot can only go ~825 F and this will now be used for my 16/1, 429 gr, custom bullet based on a Postel/Snover nose and micro-money bullet grease grooves.
Just goes to show that some problems may require more than one change to correct. This one required not only a higher temp but also a faster tempo. Pheew!