boolit shrinkage

[bigted]

i may have the answer to my own question but im gonna spring it anyway;

i have 6 diff lyman moulds and 1 rcbs mould...these are in .458....454....375 calibers. every one of them throws boolits that are small in diameter. i thought the first couple lymans were just being the lyman new run of not so good moulds but when i used all and every one casts small in diameter i began to wonder what is going on so i hypothisize this answer...really...did i just use that word?

my casting has been in cold weather...[from -20 up thru +20 degrees]. now my wonderment is this...are my boolits just acting as if i an water quenching them and getting the shrinkage from the cold weather? i just noticed this morning that the .375 boolits that i cast were nice n shiney when i dumped them into my pan and imediatly frosted completly. after i observed this i got to thinking about my small diameter problem and so thought i would post this thought and let you all type your observation on this shrinkage? or maybe i do just have small moulds...but all of them???...:popcorn:...:veryconfu...:shock:...[smilie=s:

[44man]

i may have the answer to my own question but im gonna spring it anyway;

i have 6 diff lyman moulds and 1 rcbs mould...these are in .458....454....375 calibers. every one of them throws boolits that are small in diameter. i thought the first couple lymans were just being the lyman new run of not so good moulds but when i used all and every one casts small in diameter i began to wonder what is going on so i hypothisize this answer...really...did i just use that word?

my casting has been in cold weather...[from -20 up thru +20 degrees]. now my wonderment is this...are my boolits just acting as if i an water quenching them and getting the shrinkage from the cold weather? i just noticed this morning that the .375 boolits that i cast were nice n shiney when i dumped them into my pan and imediatly frosted completly. after i observed this i got to thinking about my small diameter problem and so thought i would post this thought and let you all type your observation on this shrinkage? or maybe i do just have small moulds...but all of them???...:popcorn:...:veryconfu...:shock:...[smilie=s:
Cold should not shrink them but might help them harden faster, like water dropping. Wait a week before measuring them because most alloys will grow when the boolits age. The larger the caliber the more they grow. I cast my .475 boolits at .476" and with time they reach .478". I have had to size some again, I could not chamber without a lot of force. I do water drop.
Then again, I never cast in weather that cold. I am surprised your lead pot doesn't grow crystals! :bigsmyl2: If you pour from a ladle into the pot, will you cast a stick? [smilie=s: WOW, that's cold. Sounds like boolits are trying to escape!
I have had a lot of problems with under size molds from Lyman and RCBS. They resharpen cherries and the next run will be smaller. Seems as if only molds cut with new cherries will be right. Notice molds marked at .457" are really too small for most guns to start with and if you cast at .458" you are lucky. Lots of 45-70 guns with .459" to .460" grooves.
Could your molds all be under size? Sure! They make molds for one alloy too.
I have made a lot of my own molds and have to guess at the cherry size. Sometimes I get boolits too small so I tried freezing the mold and turning the cherry in it again. No luck so I tried it with a hot mold and cut more out of it to get what I want. Sometimes I am lucky! :veryconfu Other times I have had to turn brass laps to fit the drive bands and that drives me nuts. Even getting the gas check area right will drive a guy to drink.

[fryboy]

some alloys also cast larger - the more tin and antimony ( to a point ) the larger the boolit , lead being the densest of the three means that the more lead per ratio the smaller the casting with pure Pb being the smallest

[plainsman456]

I cast some 200 grain semi wadcutters the other day and they were smallish.
I added some tin antimony solder and they bump the sizer now,before they were going in with out touching.
I just guessed as to the amount to put in and got lucky.