Gaining diameter with age

L Ross

Active Member
No not just me, my cast bullets also. Alas, the lost innocence of youth. Back in the day I used to just cast bullets, size them with a Lyman 450 to the diameter the book told me too, lube with that nice black Lyman lube and dump them in tubs, jars, boxes, whatever until they were loaded and shot up. The only measuring tool I had was a plastic RCBS sliding vernier caliper to measure rifle case length to see if they needed to be trimmed. I never measured cast bullets. They got shot up in revolvers, some leaded, some didn't.
At the PD, we complained our Combat Masterpieces leaded because the wadcutters we cast in H&G 10 cavity gang mould were cast from hospital x-ray lead and range master would only lube one groove to keep the smoke down in the range. Those bullets never got measured. They ran through the .357" die in a Star and went to the Star loader.
Nowadays of course I measure as cast diameter, post sized diameter, use custom ground sizing dies from Chris Smith. I use a micrometer to measure because I have been told no caliper is accurate enough to work.
Getting to the point of my post finally. I now pin gauge all my revolver throats and make copious notes. I carefully size my cast bullets to half a thou smaller than the throats if I can and gleefully shoot as cast when appropriate.
I started to remeasure my cast bullets prior to loading and horror of horrors, a lot of my older bullets have gotten fat! Or bullets cast and just stored to be sized and loaded later were measured and the diameter marked on the container. A year later they have gained diameter. Typically, this has been a growth of .001" to .002".
My normal alloy is pre-2000 wheel weights, (1976 to 2000), and 1% (roughly) tin. Am I nuts worrying about this? I recently re-resized a bunch of 45s that grew from .452" to just over .453". These were cast in a Master Caster 452-230 RNFP mould and had dropped at .454 and were sized and lubed to .452" shortly after casting, then laid around here for a couple of years. My buddy borrowed my MC and using the same mould and using wheel weights with a bit of lino to sweeten cast up a gallon bucket of them and they sat in said bucket for a year untouched. When he finally wanted to size them to .451" he found the raw castings to be .456" and too difficult to force through the .451" sizer. I inherited them and as I have a Colt with .456" throats I am fat and happy.
Is this a typical scenario? Do you guys plan on diameter growth? I knew that waiting to hardness to stabilize was necessary, but when does growth stabilize?
 

Rick

Moderator
Staff member
I've not noticed that much growth. However I do have some sized bullets that have been sitting for a few years, when I get out to the shop a little later I'll measure some and see if/how much. My alloy is CWW +2% Sn.
 

358156 hp

Well-Known Member
Since you're using WW, it's likely that part of your bullet "growth" is coming from sizing springback as well. Your numbers are a bit larger than I've normally seen too, but what you're seeing is pretty normal. The best solution is to simply go shooting more often :).
 

Ian

Well-Known Member
Bullets grow. That fact has ruined a couple of range trips and cut my participation one IDPA match short. Best solution I've found if youre going to be storing ammo or loading a lot if it is to cast your bullets, size them all immediately, then let them age for six months to a year, then size again and lube as you load them. The second sizing after aging seems to maintain a long time, maybe forever.

If you limit your bullet choices and keep a rotation of your high-volume ones cast up, you will stay ahead of the curve. If you store your "green" bullets in a warm place (such as on top of your water heater) they will age much faster.
 
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fiver

Well-Known Member
stupid antimony.


you ain't lived and breathed deeply fresh mountain air till you have attempted to jack a round into your 30-30 at 7,000' on opening morning of the deer hunt aaand nope.
 

DougGuy

New Member
The longer the boolit the more it grows in diameter as it age hardens. I size throats .0005" to .001" over boolit diameter to allow for this growth. I think .002" on a 230gr RN might be a bit much I would look closer at the math, what did you use to measure with, calipers or mic?
 

L Ross

Active Member
The longer the boolit the more it grows in diameter as it age hardens. I size throats .0005" to .001" over boolit diameter to allow for this growth. I think .002" on a 230gr RN might be a bit much I would look closer at the math, what did you use to measure with, calipers or mic?
I thought both, but you know what? I'll go back and check 'em again later and report. Thanks Doug.
 

358156 hp

Well-Known Member
The longer the boolit the more it grows in diameter as it age hardens. I size throats .0005" to .001" over boolit diameter to allow for this growth. I think .002" on a 230gr RN might be a bit much I would look closer at the math, what did you use to measure with, calipers or mic?
I saw what you did there Doug....:rofl:
 

L Ross

Active Member
I thought both, but you know what? I'll go back and check 'em again later and report. Thanks Doug.
Good grief, I dug out two buckets of those .45s. I had labelled the covers with the bullet info and .456" diameter. These have not been sized. I cannot find a one that is less than .457" and the fattest are .459"! It has probably been three years at least since my friend cast them. I used a Lyman digital micrometer to measure them. I also found a tub of Magma 38 double ended wad cutters that I tumble lubed with BLL shortly after casting them to be shot as cast because they were a perfect .358" right from the mould. Nah uh, now they are .360". I am running those through the Star .358" die and putting Ben's Red in one groove. They measure a perfect .358" after they go through the Star. I'll hit them with BLL again before I load them.
 

RBHarter

West Central AR
This would explain the out of the blue feed or rather battery problems with the Hungry HP9 ...... Good thing I have a sloppier Ruger to run that ammo in now .....
 

Bisley

Member
stupid antimony

Awright then, here's another question.

I have melted antimony into lead in a Lee pot until it dissolved, and the bullets did not seem to age harden. I have cast with antimony melted (First, before I added anything else) in a plumber's furnace and then added lead and finally tin. Does the temperature (800 vs. 1200 degrees) affect how the antimony works in the alloy? Is it a real alloy if the antimony does not reach its independent melting point? Or is the melt sufficient if the antimony is added to the lead by simply pouring molten lead over the ingot that floats on top until it dissolves?

I also have two SAECO truncated-cone bevel-base 45 ACP slugs stuck in a new .451 Star die which sized at .453 a few weeks after casting and I was hoping to learn something to prevent that from happening again...

Bisley
 

fiver

Well-Known Member
I have melted antimony into my alloy before too, I have never tried melting it and pouring it into the alloy.
either way shouldn't matter, once it's in, it's in there.

what does matter is how the casting is cooled.
think about it like this, how does the BHN go up from quench cooling?
you still have 3% antimony in the alloy but one gives you 12 BHN and one gives you 18 BHN [or 22 or 24 depending on the heat and speed of the cool]
how?

it's because the antimony is 'broken up' and stuck In place affecting more portions of the alloy rather than making a long SbSn chain.
that only happens because the antimony is more of a crystal shape[you know like when you break open a chunk of lino-type and see that structure]
it opens up as it hardens and allows a little space in between.
this space is what breaks down when it is introduced to stress and is why antimony has a reputation for being brittle, it isn't really brittle it just has a weak structure that breaks down easily.

that's also why a later sizing puts the bullets to the right diameter and they stay there.
 

Ben

Moderator
Staff member
Gaining dia. with age.
UUUmmmmm..........That is happening to my body right now.
:):)
Ben
 

L Ross

Active Member
Awright then, here's another question.

I have melted antimony into lead in a Lee pot until it dissolved, and the bullets did not seem to age harden. I have cast with antimony melted (First, before I added anything else) in a plumber's furnace and then added lead and finally tin. Does the temperature (800 vs. 1200 degrees) affect how the antimony works in the alloy? Is it a real alloy if the antimony does not reach its independent melting point? Or is the melt sufficient if the antimony is added to the lead by simply pouring molten lead over the ingot that floats on top until it dissolves?

I also have two SAECO truncated-cone bevel-base 45 ACP slugs stuck in a new .451 Star die which sized at .453 a few weeks after casting and I was hoping to learn something to prevent that from happening again...

Bisley
You can stick almost any alloy in a new Star die if you don't lube the first couple of bullets you run through it first. I hand wipe Imperial Sizing Wax on the first couple of bullets I run through a new die. I stuck a .340" bullet so badly years ago the only cure was to lower it into my melting pot and liquify the offending bullet.
 

Ian

Well-Known Member
Those crystals aren't done forming and moving around once the alloy freezes. Precipitation-hardening continues for months.
 

Brad

Administrator
Staff member
You can stick almost any alloy in a new Star die if you don't lube the first couple of bullets you run through it first. I hand wipe Imperial Sizing Wax on the first couple of bullets I run through a new die. I stuck a .340" bullet so badly years ago the only cure was to lower it into my melting pot and liquify the offending bullet.
I have stuck more than a few. Never melted one out. I use a Lee type pusher in the press ram and hold the Star die upside down in the empty hole in the press from below. Loading press has plenty of umph to shove offending bullet thru.
When I test size a newly made die that is how I do it. And those bullets always get a quick smear of bullet lube of some sort.