A lot of water's gone under the bridge, and a lot of new faces have arrived here. Hence, the mention of John Haviland's reference to the cast softpoint spurs me to review the whole process.
Also, my methodology has changed over the length of the experiment.
First, I must say that I've owned well-over 100 moulds, and have NEVER warped one or even seen a warped one among the dozens of used moulds which have come into my hands. It is NOT a problem.
Now then:
I embarked on my search for a good cast softpoint with one objective: TOTALLY RELIABLE PERFORMANCE ON GAME. I don't care about ease of production, because a mere dozen or so bullets will supply almost anyone's actual HUNTING needs for several years. I say this because the regular, non-softpoint bullets cast in the same mould can be used for practice and zeroing. Therefore, I'm willing to expend considerable effort to obtain predictable and consistent results.
I consider the Nosler Partition to be my benchmark and objective for cast-softpoint performance, meaning that a correctly-functioning cast softpoint should have 2/3 of its original weight intact after recovery from a carcass. This is the reason for my belief that the softnose portion should weigh 25 to 30 percent of the total bullet weight. There are bullets now on the market that retain more weight than do the Partitions, but the Noslers have worked exceedingly well for me on scores of big-game animals. Partition performance is VERY good performance, indeed, with their typical and reliable 2/3 weight retention.
Due to my commitment to absolute certainty, I was not interested in altering the hardness of already-cast bullets. Pure lead is an absolute and known quantity, and pure lead is what I want in my softpoints...PERIOD.
Reliability also means structural integrity. Many folks have made two-alloy softpoints in the past, and mostly report good results. However, photos of their bullets clearly show a flawed joining line of the two different metals. This is an invitation to separation, in my estimation, and even if it doesn't occur, the possibility is unacceptable for my purposes.
How do I make them?
1. Melt the pure-lead in the mould by heating the mould on top of the melt in the pot. Leave the sprue plate "open" so the melting can be observed. I have discovered that using LEAD split-shot of various sizes to make-up the desired softpoint weight is very simple, accurate and inexpensive. I have some "Water Gremlin" shot of various sizes, and these ones weigh 6, 14, and 29 grains. Other sizes are available.
2. Allow the softpoint to harden!!!!! You may even want to cast a bunch of softpoints and set them aside.
3. Place a cool softpoint in the mould and fill the mould with the harder base material, leaving a big sprue on the plate. If you were to look at the bullet now, it would be pretty ugly. No matter.
4. Float the mould on top of the melt until the sprue melts on top of the sprue plate. It'll take a while, and the pot should be at its maximum setting. CAREFULLY move the mould to a dish with the wet-cloth roll in it, and cool the mould until the sprue hardens again....and a little longer won't hurt. This might take as long as a minute, because things are HOT! Avoid jiggling as much as possible, because the cavity contents are liquid and we want to avoid disturbing the relationship between the hardnesses.
That's it! The new cast softpoint can be sized normally with a well-fitting nose punch, and the new bullet can even be oven heat-treated, because pure lead is not affected by heating and quenching.
Most importantly, THERE IS NO JOINT between the hardnesses. The bullet is a seamless flawless structure, with KNOWN hardnesses at each end.
Troublesome to do? Maybe for some, but not for my purposes of seeking best-possible results. I have yet to fire one of these into flesh, but Bullshop killed a moose with one and got spectacular results. He used a higher proportion of bullet weight in pure lead, almost 50% if I recall correctly, and opined that a smaller percentage of pure lead would be even better.
John H, like MANY readers, misses one of the most-important points: LET THE SOFTPOINT COOL, and pour the base metal on top of the hardened softpoint. This avoids most of the risk of mixing the two metals which exists if both are molten. Melting the two together AFTER the base metal has been added ensures that they are perfectly fused in the locations where we want them.
I hope this clarifies the procedure for anyone wanting to try it.
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Originally Posted by Marlin Junky
