Crystalline structure time

[melloairman]

Is there a chart that shows the set time of pure lead and alloys . I have searched and come up with nothing .Marvin

[madsenshooter]

There would be many variables involved. Starting temp, material the alloy is poured into, etc.

[303Guy]

Hooh boy! Complex comes to mind. But it would be great to find such a chart. Changes in constituents, different constituents and then the variables madsenshooter mentions. Oh yes, it would be fun! But I think we really do need something like that.

[John Boy]

Marvin, Bhn aging of lead alloys depends on what is in the alloy. Example: just lead-tin or lead-tin-antimony or lead-tin-antimony-arsenic

You might want to bookmark this website ... http://www.lasc.us for additional great information and read this article for the answer to your question...
http://www.lasc.us/Fryxell_Book_Chapter_3_alloySelectionMetallurgy.ht m

In addition, buy the Lyman's latest Casting handbook. There is a whole multi page chapter in the the book on the subject

[357maximum]

Pure lead and normal binary lead/tin mixes are ready to fly immediately.

Toss alot of tin and/or antimony/arsenic/copper into the mix along with variables such as waterdropping....whew...good luck.

The closest I have come to a chart with the 4 and 5 part alloys is cast them/size and check them as soon as they are dry...put in storage for 6 months then use...most of them will be ready to go by then....although the high tin plus copper enhancement alloys are still dancing about a bit for a time frame that may stretch into years not months.


I too would love to see a chart for all the variables, but then I would have to have someone explain it to me.

[Maven]

Are you asking about phase diagrams for Pb & alloys? If so, Lyman's "Cast Bullet Handbook, 3rd. Edition" has an article by the late [metallurgist] Dennis Marshall which includes them and much more.

[John Boy]

Pure lead and normal binary lead/tin mixes are ready to fly immediately.
357 - all bullets are ready to fly when the melt hardens. But the Bhn of a lead tin alloy will change over a 2 week period- higher Bhn

[357maximum]

357 - all bullets are ready to fly when the melt hardens.


Not if one is shooting for groups they are not.

[John Boy]

Not if one is shooting for groups they are not. 357, can you explain this? To me, you are contradicting your initial post ...

Pure lead and normal binary lead/tin mixes are ready to fly immediately.

[I'll Make Mine]

I don't see a contradiction, John Boy. The latter statement pertains only to binary lead/tin alloys; most of the bullets we cast (from wheel weights or commercial alloys) are ternary lead/tin/antimony, or contain even more metals (arsenic, traces of zinc and copper, etc.).

[btroj]

The 4 and 5 part alloys are changing in hardness and possibly size for a period of time after casting. 357 Max said that he has found that even after 6 months they may be changing still more. Try shooting a 3 month old bullet with a load that was good for a 6 month old bullet and it may not work well for top accuracy, the diameter could change by a half thou or so.

Binary tin/lead alloys don't age harden at all. They don't change hardness or size significantly over time.

[357maximum]

Posts #10 and 11 about have it summed up.....thanks guys.

When it comes to ultimate accuracy I have never seen a binary Lead/tin alloy shoot better over time...then again them alloys are not ever driven to the extremes in speed and pressure by me.

When it comes to combos of lead/tin/antimony/copper I am driving them the same as I would a jacketed bullets for the most part. Them alloys seem to need some time to mature/age and finish growing.


Lead/tin/antimony boolits seem to be as good as they will get about the 4 to 6 month area, but......

The copper enhanced alloys....I cannot give you a number of days/weeks/months when them stop changing BHN or diameter, but after 6 months they seem to have settled for the most part. They may need a year or two to fully mature and to be all they can be....that answer will need to come later after my ovaltine containers of sized/checked boolits await for the passage of more time. I know for a fact that the longer you wait, the better they shoot and after sitting in a wiped out ovaltine jug they sure smell good. That is all I know for now. I have some 7mmThors that are approaching 9months and they are still gaining diameter ever so slightly.....I will wait til they hit the 1year mark and re-test them in a known accurate load ...then I will have a better clue. None of this means a 3,4,5 month old batch of 4 element boolits will be innaccurate...it just means the potential for that particular casting has not been fully realized YET.


I put a "born on date" on every container of 3 and 4element boolits...that says alot as I am not the most technical person normally.

[btroj]

Mike, could you try a few groups with bullets of various age and see what happens? Maybe prove that the difference in size and /or hardness makes a difference?

This copper thing has me intrigued.

[JonB_in_Glencoe]

Are you asking about phase diagrams for Pb & alloys? If so, Lyman's "Cast Bullet Handbook, 3rd. Edition" has an article by the late [metallurgist] Dennis Marshall which includes them and much more.

I have seen a chart/diagram of which the OP speaks...I can't find it online, I thought it was on Castboolits somewhere...it must have been in LCBH#3 as Maven pointed out. I have that somewhere.
Jon

[357maximum]

Mike, could you try a few groups with bullets of various age and see what happens? Maybe prove that the difference in size and /or hardness makes a difference?

This copper thing has me intrigued.


Already been done....and it is still ongoing and still keeping notes.

With my 21inch 7TCU @ 2512fps using H322 the boolits keep shooting tighter and tighter groups as they age. Mathmatically if I let them age about 6years they should all go into the same 30 caliber hole. :lol: The shape of the group is also getting rounder with every passing month. They gain diameter faster than they gain hardness...it is all fractional but apparently it is working. I am guessing that there is a plateu point to be reached...not there yet.

[melloairman]

I am still reading . And if a chart is found it would be nice . I use range lead mostly some from the pistol and some from the 22 range . I have a cabine tree tester and keep close tabs on my lead . I have seen it take a year to set all the way as well . But I test my bullets the day I shoot them if I am running a test of any kind so I know what is going on . Just tired of some stating that they casted a lot of pure lead bullets and a lot of lyman#2 bullets 3 hours ago and they know for sure their rifle likes pure lead over the lyman#2 . Now that they have shot some groups after the 3 hours have pasted .Marvin

[btroj]

Pretty much Mello. Bullets from some alloys change over time. Doesn't matter what they were when you cast them or sized them, it matters what they are when they go down the barrel.

Mike, that is interesting. I hope you have some set aside for that 6 year group........

[357maximum]

.............you mock :lol: but it actually could happen at 6 years, I may misplace a batch for that long, and thats only what could happen by pure accident alone. I have actually found reloading presses I forgot I had before so nothing is beyond "possible". I spent 8 hours casting with a single cavity 7mmThor mould over a monster pot of ally just for this test. This test is not going to happen overnight.

[btroj]

8 hours and a single cav mould? Are you insane?

I ink it will be interesting to see how that alloy changes over the course of a year or more. How much has the diameter changed?

I mock nothing. I have bullets I cast and lubed 10 years ago and still haven't shot. Not sure if I will ever shoot some of them.

[runfiverun]

brad member the matrix i told you about.
it takes time to form.
i don't like to shoot water dropped regular ww alloy or air cooled high tin/antimony alloys for at least 6 months.[longer is better]
that's why i try to stay waaay ahead in my casting/sizing.
it's hard to stay ahead with the lube testing,i end up with boolits and lubes scattered with little notes here and there.

[btroj]

I must not be organized enough. I have no idea how old many of my bullets are. Mine don't have a born on date at all.

[357maximum]

8 hours and a single cav mould? Are you insane?

No, but I have been asked that before :lol:

I ink it will be interesting to see how that alloy changes over the course of a year or more. How much has the diameter changed?

They were ran through a .287 die and measured .2873 when put away....now they measure .2879 to .2880. The weird part is the nose seems to grow faster than the sized portion of the boolit. I loaded some of them about a month after casting them and some are still loaded.......the boolits that were seated for dynamic nose fit to the throat are now hard to extract, not quite to the point of pulling the boolit from the case, but in time I could see it happening. Time will tell




I mock nothing. I have bullets I cast and lubed 10 years ago and still haven't shot. Not sure if I will ever shoot some of them.

I doubt I will ever have a 10year old boolit unless it is by accident.....pending the results of this test however that may change....I am seeing more time=more better, you just have to stay ahead of the changes when it comes to seating.

[btroj]

Interesting that the bullet grows differently based upon whether the particular spot was sized or not.

It does show that a load may need to be modified for seating depth based upon bullet age.

I need to stop asking questions, it just leads to more things to think about and worry over.

[lwknight]

On a not so technical note :
The biggest changes happen in the first 10 days to 2 weeks. After 3 months not so much happens except for lead/tin. Lead/tin will soften for years.

Hardnes changes from 3 months to , say 6 months or even 1 year will only be discerned by the most meticulous casters. For most , good enough works just fine.