I starting casting again after a year and a half hiatus. I bought this mold in a group buy in 2018 and just got around to using it. I have just finished the second casting session with it and I am having a problem with boolit fillout on the base. I cast about 100 each time as it didn't seem to make sense to go further. This is a 2 cavity brass mold plain base. 432-245-250gr. I find the first cavity fills out fine but the second cavity does not leave a nice flat base. I use a Lee 4-20 bottom pour pot and pour in a continuous motion. I tried the far cavity first and then push the handle to fill the second cavity. I tried reversing this procedure filling the back cavity first and then the front. Either way the last cavity filled will be rounded base. I am using range lead that tested at 12BHN on my LBT hardness tester.
I have cast using Lee, RCBS, and Lyman molds in the past and have not run into this problem. I tried casting temp from 685-750 temp with no improvement.
I am doing something wrong? I washed the mold with dish soap and hot water before use.