Good information on annealing

For anyone who wants the AMP results but doesn't want to buy one or have access to one, I'll anneal your brass with my AMP MK2 & Aztec for $.15/case or $.25/case if you want them deprimed and wet tumbled first. You cover the shipping to and from my house, but it's pretty cheap with PirateShip.com. I've done this for a number of folks, both on here and local to me, and they've all been pleased with the results. If I don't have your pilot already, you cover the cost of the pilot ($25) or the cost of the annealing, whichever ends up greater.

I end up with a bit of downtime at my work and enjoy all things reloading.

Feel free to reach out with questions via PM.

charliehorse27 said:

For anyone who wants the AMP results but doesn't want to buy one or have access to one, I'll anneal your brass with my AMP MK2 & Aztec for $.15/case or $.25/case if you want them deprimed and wet tumbled first. You cover the shipping to and from my house, but it's pretty cheap with PirateShip.com. I've done this for a number of folks, both on here and local to me, and they've all been pleased with the results. If I don't have your pilot already, you cover the cost of the pilot ($25) or the cost of the annealing, whichever ends up greater.

I end up with a bit of downtime at my work and enjoy all things reloading.

Feel free to reach out with questions via PM.

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I tip my hat to you sir. Very kind of you.

Plenty of 1000 yard benchrest records shot without ever annealing. If it works to shoot 10 shot groups at 1000 yards 1/2 MOA or better, there are a lot better things to spend your time and money on for long range hunting.
But I understand if someone is invested a bunch of money into an annealing machine that it "must be working".

Here are the facts. Brass will definitely work harden through the process of sizing, firing and sizing again repeatedly. Brass can definitely be annealed and softened by applying heat. Those points I don't think anybody can argue.

What you choose to do or not to do is what can be argued. For me, the jury is still out. For me, sticking my brass in a flame until some magical point in time is not very precise. Not very scientific. Scouring the web and online videos, I have seen so much different indicators discussed of when the brass has been properly annealed. Seen so much discussion about different levels of glowing brass. Some say you should never see any glow. Some talk about a flame changing color. Who is right and who is wrong? Got me. The biggest problem I see is no one seems to have a way to quantify what they are doing and that is what causes me to stop and pause.

Might as well talk politics or religion, pretty much the same as annealing. Good thing level minded people can realize to each his own...

MarkInPA said:

Here are the facts. Brass will definitely work harden through the process of sizing, firing and sizing again repeatedly. Brass can definitely be annealed and softened by applying heat. Those points I don't think anybody can argue.

What you choose to do or not to do is what can be argued. For me, the jury is still out. For me, sticking my brass in a flame until some magical point in time is not very precise. Not very scientific. Scouring the web and online videos, I have seen so much different indicators discussed of when the brass has been properly annealed. Seen so much discussion about different levels of glowing brass. Some say you should never see any glow. Some talk about a flame changing color. Who is right and who is wrong? Got me. The biggest problem I see is no one seems to have a way to quantify what they are doing and that is what causes me to stop and pause.

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I became interested in annealing in 2021, and like you was dismayed by varying opinions in the shooting community. Due to my engineering background, I then turned to the scientific community for information and discovered that much of the information on annealing, propagated in the shooting community is erroneous, mostly due to a lack of understanding as to the physics underlying brass annealing. I discovered the following:

1) The microscopic grain structure of brass changes as you work it, making it harder and more brittle.
2) Heating brass for a sufficient amount of time will change the microscopic grain structure of brass, returning it to its pre-worked state.
3) Brass begins to glow at a specific temperature (between 950ºF and 1050ºF depending on the exact composition) and melts at 1710ºF.
4) Brass cannot be "over annealed"; that is applying additional heat/time does not further change the microscopic grain structure beyond a certain point (unless of course you melt it).
5) You only want to anneal the neck and shoulder of a case, and not the base, so the shorter the annealing time, the less heat will be conducted down the case to the base.
6) Quenching brass does not affect its microscopic grain structure in any way.

Annealing brass is a function of temperature and time. The 700ºF that is often propagated among shooting community as the proper brass annealing temperature actually needs to be maintained for 1 hour to anneal brass. The following formula is used to calculate the time and temp to anneal brass:

B=1.38065x10^-23 (Boltzmann constant)
E=0.327x10^-18 (constant for the material, in this case brass)
T1 in Kelvin = 644º (700º F)
t1 in sec = 3600 (1hour)
T2 in Kelvin = target temp
t2 in sec = time to anneal

t2=t1*exp^(-E/B*(1/T1 - 1/T2))

This is easy to plug into Excel and if you pick 810.9ºK (1000ºF) for your target temp you will anneal in 1.88 seconds. Again note that brass starts to glow between 950ºF and 1050ºF depending on the exact composition. Using 900ºF changes the required time to 16.1 seconds.

I use the glow of the brass to gauge my temperature, understating that I am not going to over anneal if I keep it there for 2 sec or 5 sec. If you want to be more precise with the temp then you can invest in an infrared thermometer. I cannot stress enough that the key to annealing is getting the brass to between 1000ºF and 1200ºF for a few seconds (remembering you cannot over anneal unless you get close to its melting range), ensuring it is not under annealed.

MarkInPA said:

Here are the facts. Brass will definitely work harden through the process of sizing, firing and sizing again repeatedly. Brass can definitely be annealed and softened by applying heat. Those points I don't think anybody can argue.

What you choose to do or not to do is what can be argued. For me, the jury is still out. For me, sticking my brass in a flame until some magical point in time is not very precise. Not very scientific. Scouring the web and online videos, I have seen so much different indicators discussed of when the brass has been properly annealed. Seen so much discussion about different levels of glowing brass. Some say you should never see any glow. Some talk about a flame changing color. Who is right and who is wrong? Got me. The biggest problem I see is no one seems to have a way to quantify what they are doing and that is what causes me to stop and pause.

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As far as quantifying the process, a member of the forum I followed to build my annealer had access to a Vickers Hardness Tester and posted the following results on page 116 of the thread.

I keep reading all the posts on annealing. Every time I just come away scratching my head and wondering if I am really missing the boat by not annealing. If I was shooting hundreds of rounds per month, I probably would jump into the annealing pool. For now I will just buy enough brass for the life of the barrel and not worry about trying to get 10+ loads on a piece of brass.

Good information from both of you. I'm going take my time to digest this. I've actually paused my reloading process trying to figure out which way I want to go. Primers have been popped and they have been through the tumbler.

I was playing around this afternoon with some junk brass that I kept for either making tools or experimenting with. I tried the drill, socket and torch method for different amounts of time. Tried some with templilaq and some without. I'm not sure I proved anything to myself though. Other than if you use the templilaq, you need to then put time and effort in getting it cleaned out to the neck. I was a bit amazed at how good of a heat sink the socket is. The brass discoloration seemed to stop right where the top of the socket was.

Thanks for sharing the information.

Mark37082 said:

I keep reading all the posts on annealing. Every time I just come away scratching my head and wondering if I am really missing the boat by not annealing. If I was shooting hundreds of rounds per month, I probably would jump into the annealing pool. For now I will just buy enough brass for the life of the barrel and not worry about trying to get 10+ loads on a piece of brass.

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I was in the same camp as you until 2021 when two things happened for me, both peaking my interest in annealing:

1) Brass became nearly impossible to find and I was looking for a way to make what I had last longer.

2) My shooting partner gained access (one of ten people) to his friends private range with a roof covering 2 concrete benches and steel at every 100 yards out to 1000.

Under 300 yards, I don't know that annealing makes any difference on target, but at 1000 yards you want to maximize consistency, and for me annealing made sense to that end. I also changed to loading for accuracy over velocity to help with #1 (primer pockets last longer) and #2. Unfortunately my friend moved last year so I no longer have access to that range. But annealing has become part of my loading process, so I continue to do it.

After reading your post I got my junk brass out again. Went back to heating them up and before I would see any kind of glow I started to see a discoloring of the flame. This isn't good is it. Doesn't it indicate that one of the alloys of the brass is burning off?

MarkInPA said:

After reading your post I got my junk brass out again. Went back to heating them up and before I would see any kind of glow I started to see a discoloring of the flame. This isn't good is it. Doesn't it indicate that one of the alloys of the brass is burning off?

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What you are referring to is dezincification. Dezincification is typically defined as the leaching of zinc from copper alloys in an aqueous solution

According to AMP's studies, "Dezincification of brass can occur because of chemical attack, butheating brass, even to high annealing temperatures cannot cause dezincification unless chemicals are present. The zinc content of the alloy cannot burn or melt out up until boiling point (Appendix 1 - 1.6)."

You cannot boil the zinc out of brass at the melting temp of zinc, zinc is molecularly bonded to the copper and melts at the melting temp of cartridge brass. It's a homogenous solid without any secondary phase groups floating around.

Dezincification is yet another example of misinformation propagated in the shooting community by those not understanding physics and chemistry. They look up the melting point of zinc and assume it melts out of your brass when the brass reaches that temperature. The boiling point of hydrogen is -252.9°C, by this logic it should have boiled out of water at room temperatures. The zinc-copper bond is stronger than the zinc-zinc bond and requires higher temperatures to be broken.

The color change in the flame is more likely some chemical burning off (lube or cleaner or carbon residue) or it may be as the brass starts to heat, the energy it radiates in the visible light spectrum is changing the the perceived color of the flame. In any case, you are not harming the brass.