What is tempered lead shot?

Falconflyer

Falconflyer

CGN Ultra frequent flyer
Rating - 100%
31   0   0
Location
Between the mountains and the prairies
I was perusing Clever’s website and I see they offer a target shell that is loaded with “tempered” lead. It’s featured in their T2 Competiton shell and claims it to be a “new production technique”. I’m no metallurgist but I’ve always understood tempering will make steel softer and I wonder why one would want to make lead shot softer as most manufacturers would like to make they’re shot harder than pure lead. That’s why they add antimony to premium shells. So does tempering lead make it harder? Softer? Is this some sort of marketing gimmick or is there something to it?
 
I'm not familiar with the specifics of Clever's claim, but "tempering" can mean more than just softening heat treatments. The best examples are the age hardening treatments applied to aluminum, which are assigned 'T' codes to indicate the degree of hardening. For example, 6061-T6 has the 'T6' temper code, which is the strongest temper available from this alloy.

As a side note, people really need to stop taking their metallurgical cues from steel. Steel is one of the strangest alloys out there, it's behaviours and characteristics are unlike those of almost any other metallic materials. As a rule of thumb, do not try to apply anything you know about the metallurgy of steel, to anything that is not steel.
 
We have become very susceptible to words that sales and marketing people use - whether correct or not. I know with lead that has some antinomy added to it - heat to just below melting point, and then douse in cold water - that will become harder than you started with. Without antinomy in there, about a waste of your time. Maybe a marketer calls that "tempering"? Maybe somebody discovered a way to do that without using antinomy?

Is more than adding heat - in that case, it ALSO includes very rapid cooling - I likely understand it wrong, but as if the molecules in the heated metal get to re-arrange themselves into a new pattern - a new "matrix" - powered to do so by the heat energy, and then get "frozen" in place by the cooling - cool too slow, and they go back to the arrangement they used to be in. But I might have that all wrong.

So you can have shot made from 97% lead and 3% antinomy that is softer or harder - depends how it was processed. Simply telling you that it contains "x" amount of antinomy, does not mean that it is hard - and having more antinomy content does not mean it is harder - if it wasn't heated and cooled appropriately. Telling you that it was heated and cooled, without telling you whether there is any antinomy in there, can result in "softer" lead, as well - even though "tempered".
 
Last edited:
I am guessing that you would have to ask someone who sells "chilled shot", whether that is the same as "tempering" and whether what they sell is harder than plain lead shot - regardless what they call it. I believe that "hardness" is typically measured and reported using a Brinell scale - so a material with a lower Brinell number is usually softer than a higher Brinell number. I used to have a tool made by Lee Precision that would let me come up with a Brinell Hardness Number (BHN) for lead bullets that I was casting - I do not have that any more. You might find on various firearms and other things, little "dots" from when the hardness was checked at that spot. There is likely other additional scales that report similar - a numeric value that represents "hardness" of the material.

Google that, and see that pure lead typically has Brinell Hardness Number (BHN) of 5 - I found some alloys with tin and antinomy as high as BHN 28 - maybe they go higher than that? And I do not know what would be the "cut-off" to call something "hard" lead shot - is that BHN 7 or 22? - either would be "harder" than pure lead.
 
Last edited:
I’ve been aware of the Brinell hardness testing for some time but I’ve never used the equipment. I’ve also known for a long time about adding antimony to lead to harden it. Soft lead shot is usually around 2% and hard shot 5 or 6% antimony. The raw price of antimony has just about tripled in the last 3 years so I was just wondering if this so called “tempering” of lead was something that the shot shell manufacturers had started doing instead as a cost cutting procedure but the more I’m learning about it the more I’m leaning toward it being a marketing thing.
 
Falconflyer - technology moves ahead on us, and is quite possible that there is a way today to make lead harder by heat treatment, without using antimony in the alloy - but I do not know that. I also notice that marketing makes some pretty outlandish claims that people buy into - to cause them to spend their money - which, I think is the point of the marketing industry - to get you to spend (or at least to "want", if not "need", that product) - not necessarily to give you truthful information.
 
BattleRife said:
Steel is one of the strangest alloys out there, it's behaviors and characteristics are unlike those of almost any other metallic materials.
Click to expand...

Of the common metal alloys, yes.

Interesting side note:
The metallurgy of plutonium is probably the most intensive study. Due to the unique energy level of it's valence electrons, it has a very large number of crystalline phases and can change one to another in just a few degrees temperature.
 
Falconflyer said:
I’ve been aware of the Brinell hardness testing for some time but I’ve never used the equipment. I’ve also known for a long time about adding antimony to lead to harden it. Soft lead shot is usually around 2% and hard shot 5 or 6% antimony. The raw price of antimony has just about tripled in the last 3 years so I was just wondering if this so called “tempering” of lead was something that the shot shell manufacturers had started doing instead as a cost cutting procedure but the more I’m learning about it the more I’m leaning toward it being a marketing thing.
Click to expand...

I hope that you are correct, and why I think that I might misunderstand - simply knowing the % antinomy content, without knowing the heat treatment - to result in a BHN - does not let me know if one shot is "soft" and the other is "hard". As above, I do not know what is the "cut off" between soft and hard for lead shot - to my understanding, knowing the antinomy content is only part of the information needed to know? That BHN 28 alloy that I found on-line was 19% antinomy, then some tin and 70-something percent lead - I suspect that is much harder stuff, compared to pure lead. But I do not know how "hard" it has to be, to be called "hard" lead shot.
 
Last edited:
An additional thought - there might be more to it than just "hardness" - I think some materials get very brittle when they get "hard" - so they shatter into small pieces really easily - likely not a good thing for shot? So must be at least a "hardness" to account for, but also a "brittleness" (or lack of that) - "lack of brittleness" is likely the "toughness" that Post #8 mentioned, but I do not know that either. I know from higher carbon content steel alloy, I can make a knife edge or drill bit edge or a lathe tool edge very hard and quite sharp, but it will crack or fall apart easy with about any bump - and then other steel alloys like "tool steel" seem to stay sharp even when about red hot - but that is from examples of playing with steels - as per above post, might not be applicable to other metals.
 
Potashminer said:
I hope that you are correct, and why I think that I might misunderstand - simply knowing the % antinomy content, without knowing the heat treatment - to result in a BHN - does not let me know if one shot is "soft" and the other is "hard". As above, I do not know what is the "cut off" between soft and hard for lead shot - to my understanding, knowing the antinomy content is only part of the information needed to know? That BHN 28 alloy that I found on-line was 19% antinomy, then some tin and 70-something percent lead - I suspect that is much harder stuff, compared to pure lead. But I do not know how "hard" it has to be, to be called "hard" lead shot.
Click to expand...

The soft and hard that I’m referring to is in regards to shotgun lead only. Studies on the matter that I’ve seen don’t list a Brinell hardness factor for these and only go by percent antimony, it seems to be the industry standard used by the manufacturers. For instance, the cheap promotional loads range anywhere from 1.5% to about 3%. Winchester Super Target and Remington Gun Club are around 2% whereas Kent is usually around 3% to 3.5%. The more expensive target ammo such as AA is 5 to 5.5 and Remington STS are closer to 6% but I know of no manufacturer that goes higher than that. Keep in mind I’m talking about target loads and not hunting loads, I don’t know if they go higher or not.
6% seems to be what the manufacturers have decided is hard enough not to deform when being jammed through the forcing cone and choke tube and will produce tight patterns with few fliers.
 
You must log in or register to reply here.
Back
Top Bottom