Sizing Cast Bullets

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R. Johnson

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I've been reloading for a couple of years now and decided to start casting. I've got most everything I need to start now, but I don't quite understand this sizing stuff. How do I know which sizing die to purchase? How do I know what size the bullet needs to be? And why doesn't the bullet come out of the mould the correct size?
 

NikatKimber

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In short, different alloys of lead shrink at different rates; therefore the mold cavity must be slightly oversize to ensure that no bullets are too small.

In general (as in, don't quote me on this) the rule of thumb is one thousandths (0.001") larger than the corresponding jacketed bullets. IE, for .38 / .357, the jacketed bullets are .357", and the cast lead bullets are *typically* sized to .358".

There are exceptions to this, and then some guns may shoot better with different size bullets. If you really get into it, then you will learn all that down the road.
 

Blitzfike

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I've been casting and sizing bullets for almost 40 years, and I'm still learning. Some of the Lee molds I use when using
wheel weights for my lead source cast bullets that slide through the lee sizing dies unchanged. Softer alloys and harder
alloys may both require more effort to size. For rifle bullets, I almost always use a Lyman size and lube press with hard
high speed lube. I have to use a heater with that combination or the lube won't flow in the press. Liquid alox with the
cast bullets rolled in it to give a uniform coating is usually all I need for 9mm hard cast bullets from the Lee mold and die.
All of the magnum handgun cast bullet loads get the high speed lube. We have been shooting 30-30 and 8mm mauser with
hard cast gas checked bullets with great success. They are accurate and have much softer recoil. very pleasant to shoot.
I even have a 00 buckshot mold from Lee. All I have cast at this time is hard alloy, but I will be casting some dead soft
shot in the near future. I bought a Lee lead hardness tester and when making up large batches of casting ingots, I use the
hardness tester adding linotype, tin and other secret ingredients (antimony) to get the hardness I want. I find that water
quenching the bullets out of the mold gives me a bullet that is just the right hardness for my plinking and target shooting.
Lead is somewhat like aluminum in that it will change its hardness as it sits for long periods of time after being annealed
or tempered. I did some experimentation with tempering bullets but figured out that for all intents and purposes (my purposes)
tempering beyond water quenching isn't worth the effort in terms of increased accuracy of the bullets. I'm fortunate in that
I have a labratory grade temperature controlled oven to play with.
One other area to be aware of is that if you are casting for a revolver, the cylinder throat diameters have a larger impact on
accuracy and leading than the bore diameter. If you match the bullet diameter to the chamber throat diameters, you will see
a large improvement in performance. Just some of the observations I've made over the years. Good luck and good casting. Blitzfike
 
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Matt Basterson

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i cast my own bullets, i don't enjoy it, it's just a chore that's gotta be done. that's why i use the lee molds that are intended to drop loadable bullets right from the mold. i use plain wheelweights, drop'em into water from the mold, then lube with liquid alox. they work just as well or better than anything i can buy. they fit all my guns that i've shot'em thru, without leading, and the accuracy is great. i haven't had to size the bullets that i cast for my 45-70 either, just alox and shoot.
 

T.R.

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One other area to be aware of is that if you are casting for a revolver, the cylinder throat diameters have a larger impact on
accuracy and leading than the bore diameter. If you match the bullet diameter to the chamber throat diameters, you will see
a large improvement in performance. Just some of the observations I've made over the years. Good luck and good casting. Blitzfike


This.
 

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