ok bare with me .bought lee 400 gr (2 cav) -475cal mould-could not wait for balisticast any longer the bullet comes out 375-390 gr.i do this at work with a ac torch takes 3-5 minutes to melt ww .i dip some scum off top of pot then use a ladle i welded together to pour into mould,i know this realy is not the way to do it had to do something to try my new mould,these are my first bullet ever. i thought the ww wuold make the bullet come out heavier than stated on mould.read somewhere 5-7 % heavier? im waiting on a lyman casting kit from midway to get serious,but do i cook longer to get impurities out to get heavier bullets?

When the metal reacher about 800 degrees, you flux the mix with bees wax or bullet lube. This gets the tin, lead, anamony, to mix together. Using only wheel wt.s should give u a heavey bullet. But with wheeel wts you never know. Worry more about the finish dia. of the cast bullet. The have to be fat enought to be sized to the proper dia.

The bullet weight listed on a mold is only a ball park figure of what your results will be.

For instance, the Lee 400 mold I have, which is one of their prototypes, produces a lubed bullet that is darn near dead on 400 gr cast from wheelweights.

My ballisticast which I requested to produce a 440-450 gr bullet comes out 459 gr when lubed and gas checked, and cast from wheelweights.

As was mentioned, finished weight isn't really important, it's casting consistant bullets that matters.

As Paul stated the weight listed on the mold is a figure that you can count on pretty reliably if you use a proper 20-1 mixture since that is what the manufacturers use.

In the instance of Lee molds (got rid of all of mine) I have never been able to get those aluminum block molds to get as heavy as with iron or steel block molds. Don't know what produces this anomoly but there you have it