Cast a test example bullet with Cerrosafe?

[greenjoytj]

Can Cerrosafe be used to cast a test bullet, strictly for measurement purposes?

Why?

I have a Lyman 452664 mold that is supposed to cast .452” RNFP bullets for my 45 Colt.

After sizing to .452” I have noticed the sizing die smears a tongue of lead (20:1 Rotometals alloy) upward on the side of the bullets ogive along the mold part lines.

This extra displacement of lead only occurs on the part lines, it effectively widens the upper drive band so much so that it interferes with complete chambering of the cartridge. My Wilson and Dillon plunk gauges can’t detect the the misfit ctg’s. The rims are sometimes left standing up off the cylinder just enough to prevent cylinder rotation. Very annoying.
I must test fit every round into a cylinder chamber and those that have their rim standing high, get a light tap to dent the lead smeared up the part lines and seat the rim down.

So the result is my mold cast out of round bullets, the sizing die proves this and causes the upward smearing or displacement of lead along the mold part lines which the widest dimension.

I want to determine if my mold is defective, or if its just my casting technique (mold iron too hot) thats causing of the out of round bullets.

I suspect high heat is expanding the 4 cavity mold iron block length wise along the part line, there by increasing the bullet diameter in this dimension.

I think a virtually cold cast with Cerrosafe my help determine the cause of the out of round bullets. If the Cerrosafe alloy bullet drop and measure with the same diameter perpendicular to the part line as along the part line I’ll know my mold is good. Then just need to work on casting temperature and cadence.

[Newboy]

Be aware Cerrosafe is not dimensionally stable over time.


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[DocSavage]

Cerosafe is pretty expensive for casting bullets. Who made the mold Lyman or RCBS if RCBS they replace the mold. I've never had a mold that was out of round so no suggestions on solving the problem.

[blackthorn]

I would say no you cannot due to the fact that Cerosafe will be undersize up to one hour after casting and then it will grow thereafter. This means you might could get an accurate reading if you measure at the one hour post cast point. Before or after will not be accurate. If I were going to try what you propose, I would likely try a Sulphur (80%) graphite (20%) mix which will have really minimal shrinkage/growth after casting.

[bangerjim]

Cerosafe shrinks when it cools. Then expands later as said!! That is it's properties we use in certain circumstances.

I have a LOT of an alloy very close to the Cerosafe mix I use for lots of stuff, but never casting boolits and relying on it's dimensional stability.

If you have the alloy already, try it and let us know how that works out for you.

banger

[JonB_in_Glencoe]

I suspect high heat is expanding the 4 cavity mold iron block length wise along the part line, there by increasing the bullet diameter in this dimension.
I am very skeptical of this idea ^^^

...
I have made test cast with a cold mold more than once, the boolits were same as when cast with a preheated (but not over heated) mold...a over heated mold will likely cast .001 smaller, in my experience.

So, I would just cast them with your regular alloy in a cold mold. You'll get wrinkles, but you can compare them with the boolits you have cast during a regular casting session...I bet dollars to donuts, that they will measure the same.
That's my 2¢

[justindad]

I suspect high heat is expanding the 4 cavity mold iron block length wise along the part line, there by increasing the bullet diameter in this dimension.


Thermal expansion of metals is the same in all directions, so I can’t see this being possible. The mating faces would have to be significantly hotter than the rest of the mold, which would probably warp your mold permanently if you were able to achieve such a temperature gradient. Heat tends to spread out evenly across a block of metal, and molds should be designed to do that intentionally.

Are the cavities in alignment? I have had eccentricity cavities create out of round boolits, which was first observed in the sizing marks.

[Soundguy]

Why not size them nose first...

[Mk42gunner]

Lyman molds are normally designed and specced for using Lyman #2 alloy, anything else will have a possibly miniscule variation.

How they expect #2 alloy to be consistent with the known variation of WW as the main component, I have no idea.

Robert

[Soundguy]

Yup..using softer alloy might get you more shrinkage.

[greenjoytj]

Why not size them nose first...

I will try that.
I do have a press mount LEE nose first push through .452” die.

I forgot I had this style of sizing die. Last time I uses it to size a SAECO #955 .452”/.454” 255 gr. RNFP that dropped at a huge .456” dia. Obviously this is designed for old Colts with .454” barrels.
Nose sizing that over size (for a modern Ruger in 45 Colt) beast created huge base finning that I couldn’t figure out how to remove so the base edge wasn’t damaged.
Base first sizing that #955 would smear away 90% of the crimp groove.
Still it was a good bullet. Maybe I’ll cast it again if I can’t solve my issue with the Lyman 452644.

[Dusty Bannister]

Yup..using softer alloy might get you more shrinkage.

Lead and lead with tin mixes have the same shrinkage rate. Antimony will reduce the shrinkage. His alloy is as small as it will cast.

Is it possible that the mold blocks are off set a small amount? This will show up as nearly wiped out grooves on one side and almost no contact with the driving band on the other side of the mold seam. This is common if the alignment pins are incorrectly seated, or if there is a defect in the alignment hole on the opposing block. Common to notice light showing between the blocks when they are closed.

[Soundguy]

Lead and lead with tin mixes have the same shrinkage rate. Antimony will reduce the shrinkage. His alloy is as small as it will cast.

Is it possible that the mold blocks are off set a small amount? This will show up as nearly wiped out grooves on one side and almost no contact with the driving band on the other side of the mold seam. This is common if the alignment pins are incorrectly seated, or if there is a defect in the alignment hole on the opposing block. Common to notice light showing between the blocks when they are closed.

I don't know.. tin shows a different shrinkage rate than lead.. at 100% . I'm trying to read the pdf on my phone but it is hard.. the fryxel casting document has the shrinkage rates.. again.. hard to do on a phone. maybe someone can post it here.. or the LASC club page has a breakdown too.

[greenjoytj]

Is it possible that the mold blocks are off set a small amount?
This will show up as nearly wiped out grooves on one side and almost no contact with the driving band on the other side of the mold seam.
This is common if the alignment pins are incorrectly seated, or if there is a defect in the alignment hole on the opposing block.
Common to notice light showing between the blocks when they are closed.

Thank for the tip, I’ll look for light between blocks while closed.

[greenjoytj]

Is it possible that the mold blocks are off set a small amount?
This will show up as nearly wiped out grooves on one side and almost no contact with the driving band on the other side of the mold seam.
This is common if the alignment pins are incorrectly seated, or if there is a defect in the alignment hole on the opposing block.
Common to notice light showing between the blocks when they are closed.

Dusty You are correct. My Lyman 452664 cast bullets sized through my LEE nose first up sizing press mounded die, show lead smearing precisely only to the RHS of the mold part line. Rotate the bullet 180* and the lead smear starts abruptly at the mold part line smearing to the RHS again.
When I measure my bullet dia. I must hold the micrometer to the side of the part line.

[Conditor22]

Lee sizing dies have been known to run a little small and are a little rough from machining. I polish the entrance and lightly polish the sizing portion of all my sizing dies. they work much better after I do that.

what mold are you using?

How hot is your pot?

What are your boolits dropping at?

measure the boolit before and after you size it

IF the lube grooves don't line up at the marriage line your alignment pins are off.

I'd start by scrubbing the face of the mold clean (nylon brush for aluminum mold, brass brush for steel mold)
close the mold and see if the 2 halves will slide against each other when closed (this means your alignment pins have moved and the mold needs to be clamped on a piece of hardwood without the handles and the pins are tapped back in with a properly sized punch until the mold have don't slide when closed. Hold the closed mold halves up to a light and see if there is any light shining through, if so you went too far and have to tap the pin on the side the light shines through the most back a little.

you can pressure pour/cast a cold mold and get fairly good results (hold the sprue plate tight to the spout (after letting a little lead through the spout to remove any cool lead) raise the pour the boolit for a few seconds, keep pouring as you lower the mold creating a puddle.