I am having a problem I don't understand. My cast boolits are coming out much heavier than the advertised weight for this mold. The mold is a Lyman Devastator No. 429640 single cavity 240 Gr. mold. My alloy is 250 Gr. 50/50 solder to each 1 Lb. COWW. I am casting at 725 degrees. Boolits fall out of the mold and look fantastic after the mold warms up. I powder coat with Eastwood Lime Green powder and the HP cavities are cleared of any excessive powder before baking. I bake these standing on their base at 400 degrees for 20 minutes. The boolits come out of the oven to a water bath and all boolits are well coated and stand up to a 3 Lb hammer test without shedding any of the coating. I am sizing to 0.431”..The problem is these now weigh 261 Gr.s. I have checked my Lyman / Ohaus beam scale with Lyman Check Weights and an electronic scale with the same results. . What is causing the excessive weight?? I understand the boolits may come out 4-6 Gr;s heavier than the advertised weight but 21 Gr's. seems very excessive.
I am also looking for advice on loading these 261 Gr. boolits for my S&W 24-2 44 Special and I will be using Hodgdon HP 38 powder as I have 14 Lb of the stuff and powder is expensive to buy right now. I can’t find any reloading data using a boolit heavier than 240 Gr. for this cartridge using this powder. I am wondering if 3.0 Gr’s of HP38 would be a good starting load? These will be plinking boolits. I appreciate all your advice. Thank you.