vmwilson
posted this
23 February 2014
Recently had that problem. Had mixed up a good batch of alloy that worked fine in a 9mm (Lyman) mould. Getting to the end of things and found a batch of rifle bullets I'd cast years ago and decided to add them to the melt and bingo things went to pot.
Wasn't too sure of what was in those bullets so I emptied the pots which turned out to be around 11 1 lb ingots. Being lead shrinks the most of the 3 main materials I added 10 ingots of lead from cable sheathing to the batch. My first alloy had a BHN of about 18 and adding that lead dropped this little concoction to 14 on the following day. And they now released from the mould just fine.
I'm sure those rifle bullets were originally cast with NO antimony added as I have never bought any of the stuff back then. But I used to get some solder bars used for wiping cable splicing sleeves so I'm wondering if I was just way too rich on tin. All guesses on my part at this stage but adding that lead turned the trick for me.