What the?...My bullet is not round

[Schuetzum Phast]

What is going on here. This is the second time I've used this mold (lyman 457125). The first time the bullets came out very nice but I was using COWW. Today I'm using a mixture of 3 parts lead and 1 part mono. The dropped bullet just forward of the driving band is leaving a flat spot on the side. Measuring .432 and spinning the bullet in the caliper going up to .451-.452. I tried adjusting the temp, I stored the mold properly and cleaned it two different times when I noticed the slump in the side of the bullet. Seems like it's doing it in the same spot but I can't feel anything on the mold like I can on the bullet. I'm trying to achieve a 13-14 BHN. Do I need to add something to the mix to fill out the mold better or what? I'm open to suggestions. Thanks in advance.

~SP

[jsizemore]

Check the vent lines. Try pouring down the side of the sprue hole so air vents. Mold might not be up to temp. Don't admire your results, pick up the casting pace. My #50 mold has to run a little hotter alloy and quicker casting pace to keep the mold blocks hot enough for proper fill out.

[Defcon-One]

I agree, hotter mold, hotter lead will likely fix your problem. Your pot temp should be around 725 deg. F, maybe a bit higher (Don't go over 775 deg F.). Your Tin % is already high enough to promote good fill-out, but it won't flow at too low of a temp or in a cold mold.

You are using 2.25% Tin, 4.75 % Antimony 93% Lead. I'd try 6:1 Lead/Mono cutting the Tin and Antimony in half. That would get you close to Clip-on Wheel weights with 1% added Tin. I'm saying, why waste all that good Monotype.