When a mould lists ".430" nominal diameter" what does that mean? Will it drop smaller or larger most of the time, and by how much?
Can bullet sizers make a bullet larger?
When a mould lists ".430" nominal diameter" what does that mean? Will it drop smaller or larger most of the time, and by how much?
Can bullet sizers make a bullet larger?
It means the mould will cast a .430" diameter bullet if you use the same alloy, and the same casting temperature, the mould is made for...with a caveat.
That is the part where some mould makers state that finished diameter may be as much as (say) .002" larger than nominal. When you see that, it will usually be a maker who uses a cherry to cut the cavity. His cherry is made a little large so it can be resharpened a certain number of times. As it gets resharpened, it gets smaller.
When it's new, it cuts the cavity a little over nominal. After it's been resharpened enough times to become too small, it's replaced with a new one.
Lathe bored moulds will usually be cut to produce right at nominal diameter when the company's 'standard' alloy is used. If you cast with a different mix, you can expect a different result. Lyman's standard is Lyman #2 alloy. Somebody once said Lee's standard is wheelweight metal. I don't know if that's true, but wheelweights are highly variable...so it sounds like a bad idea to me.
If you order a mould from a custom maker, he will often ask what alloy you intend to use. Then, he will adjust the cavity size to meet your requirement when using that alloy.
A bullet sizing die can only make a bullet smaller when it's used as designed.
CM
Retired...TWICE. Now just raisin' cows and livin' on borrowed time.
What if you cast with pure lead, would you generally get larger or smaller bullets?
Slightly smaller diameter, but also heavier CB's from pure Pb.
Smaller with pure lead but moulds designed to drop pure lead should be larger to accomidate that.
Aim small, miss small!
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