Changing size of a bullet, sized and unsize.

[357shooter]

Curious about how bullets change size over a period of a few weeks got me started on a test. With different bullets poured and measured all at the same time, some of the results are interesting. These bullets are spread across 3 different moulds.

A fairly good single representative makes it easier to see what is going on. Other bullets followed a similar pattern, they vary a bit in the amount of change from week to week.

Here are 2 bullets from the same cavity of a 358-429 mould. The green line was lubed in a Lyman 450 with a .360 die within hours. The size remained the same because it wasn't big enough, but was lubed. The blue line is the other bullet, unsized and unlubed. Maybe not the perfect scenario, but that's the way it worked out.

It's a three week period with each bullet measured on the seam.

I don't think this is earth shattering, but figured some might be interested in the result: (note: all comments input and feedback are appreciated)

http://i878.photobucket.com/albums/ab341/prgallo/Aginglead.png

[Bret4207]

Interesting. I was under the impression they "grew" and stayed at that size. I'll have to do some checking myself....if I can remember!

[Bass Ackward]

I love experimenters and testers. They are the ones that prove to others that there are no rules.

Were these bullets marked so that measurements were done in the same place every time?

I ask because I also find that the expansion is not uniform either which may explain the contraction. But I do find that they can get smaller as the hardness is lost as well which is why I store unsized.

[357shooter]

Interesting. I was under the impression they "grew" and stayed at that size. I'll have to do some checking myself....if I can remember!
I have the same remembering thing. Hoping it's age related and not lead related! :p:p

What confuses me, and I'm not sure of the answer is, why didn't the sized bullet gow/shrink as muck. The sizer didn't size it, but did put a thin coat of lube on the bullet. I'm speculating that once it's coated with lube, air isn't getting to the lead.

Just a thought.

What hasn't been tested yet is, what happens to the diameter when sized at week 2 or 3. Does it still shrink?

The pot is heating up. The NOE mould thermometer is newly installed and micrometer is out. More testing is on the agenda.

The alloy used in the graph was soft, 98% lead 2% solder. Going to verify if a lead/WW (still soft though) mix reacts the same way. I expect they will, however I didn't expect these results either so who knows.

[357shooter]

The mark used is the seam, so it would be consistent. I did enough bullets that bulging seams (with a little flash) were omitted from the test, and measured each a few times to minimize operator error.

The expansion is definitely not uniform.

As far as storing unsized, that's a good point. I had an accuracy issue this week and traced it back to a change in when I sized.

I cast smallish numbers of bullets at a time, 1,000 or less; as I shoot the same number all year long. So basically a month at a time are cast.

I was lubing/sizing and loading a week at a time, and it was working great.

Tried to improve the process and cast and sized everything that same weekend. Then loaded a week at a time.

Accuracy dropped off at the range.

The pre-sized/lubed bullets never got as big as "expanded" then weekly/lubed/sized bullets. There isn't a line for this on the graph in case you are looking, I'm just saying the fat bullet sized w/.360 die is bigger than the one size right away. At least with my alloy, mould etc...

It mattered.


I love experimenters and testers. They are the ones that prove to others that there are no rules.

Were these bullets marked so that measurements were done in the same place every time?

I ask because I also find that the expansion is not uniform either which may explain the contraction. But I do find that they can get smaller as the hardness is lost as well which is why I store unsized.

[243winxb]

My test started on 3-27-10 on 44mag bullets shows they are not getting larger in diameter. Made from magnum shot/6% antimony, then oven heat treated for 1 hr. @ about 450 degrees, just below slump, then water cooled. Boolits were sized, heat treated, relubed. Every time the bullet growing subject comes up, i remember to go measure. Still NO growth. 2-5-11. Maybe the lube does protect/change the outcome? Lubed in a LYman 450, no lube on the nose. I have many air cooled,sized & unsided bullets sitting for different periods of time, i never have seen any diameter change. They may get harder if water dropped, but i do not test for hardness, other than a thumb nail.

[357shooter]

My test started on 3-27-10 on 44mag bullets shows they are not getting larger in diameter. Made from magnum shot/6% antimony, then oven heat treated for 1 hr. @ about 450 degrees, just below slump, then water cooled. Boolits were sized, heat treated, relubed. Every time the bullet growing subject comes up, i remember to go measure. Still NO growth. 2-5-11. Maybe the lube does protect/change the outcome? Lubed in a LYman 450, no lube on the nose. I have many air cooled,sized & unsided bullets sitting for different periods of time, i never have seen any diameter change. They may get harder if water dropped, but i do not test for hardness, other than a thumb nail.
The test in this is case of over the first 3 weeks after casting only. The final measurement is right at the starting measurement. I'll track longer to see what happens in the coming weeks. If I measured the day of casting, then again in week 3 it sould have seemed to me that there was no change in diameter. But there was, cause I measure the same day each week.

As far as growing over a long period of time, I don't believe I addressed that at all and certainly made no such claim. My bullets don't last more than a month anyway. However this topic matters in my case because the size does change in the timeframe that I load and shoot them.

[XWrench3]

well, by the end of the chart, the outcome is near identicle. the difference is in weeks #1&2. by week 3, they are both very close to the same size. it is interesting how it appears that the lube is inhibbiting swelling. i may also have to join in, and test with and without L.L.A. it gets smeared over the entire boolit, so if it is an air issue, the boolits shoul be completely sealed (i lube twice). mine will be w.w. alloy, air cooled. it will be a few days till i can get out and cast some. kids = time eaters!

[1Shirt]

Interesting!
1Shirt!:coffeecom

[243winxb]

http://castboolits.gunloads.com/showpost.php?p=1083280&postcount=14
my .476 boolits grow to .478 with a few weeks. Comments like this is why i started taking measurements. Hard to believe a boolit will grow .002" :confused: I guess anything is possible, depending on the alloy used.

[357shooter]

Bigger bullets may matter too. A 44 or 45 may be different than my 357.

[NSP64]

357shooter. This is interesting.
What would happen if you took some unsized boolits and sized them at week 2 when they were the largest?
Would they shrink more?
Berrry in-ter-es-tink, Berrry in-ter-es-tink.

[357shooter]

That is a great question. I cast more today an plan to give it a try. One point is that it is important in this case because the size it marginal, right on the borderline of what I'm looking for.

If they all dropped at .3605, then ended up at .3605 after 3 weeks it wouldn't have matter so much.