Annealing Brass Cases & How to Do It OR What Those Colors on Rifle Casings are & How to Recreate Them.

If you have been reloading or researching reloading for any length of time, you have probably heard of the term “annealing”. If you haven’t, then you have seen evidence of it before. If you look at the necks of some ammunition, you’ll see some almost-rainbow colors somewhere just down from the shoulder of the case. That is evidence of annealing. There are some advantages for reloaders to use this process as well, and the purpose of this article is to familiarize you with the concept and demonstrate a simple way to anneal your cases.

Annealing is the stress reduction of the brass to prevent it’s becoming brittle and cracking or breaking. All bottlenecked cases are annealed during production. This is done to prevent the case from cracking or otherwise failing. Military cases are typically required to have evidence of annealing (hence why they have the visible coloring). For the reloader, annealing your cases has a number of benefits. As I mentioned earlier, brass gets hard and brittle through it being worked and also with age. Obviously, reloading is in part the resizing of the cases back to the proper size for reuse. Cases loaded several times will get brittle and crack eventually. Annealing these cases will prolong their useable life significantly. With reloading components in general rather hard to get right now, it makes sense to try to get as much life out of your brass as you can.

Also, case conversions can work brass significantly in the conversion process. Sometimes this is significant enough to cause cracks in the case within the first or second firing. If you put very much work into converting them, you really don’t want to have to toss your cases after the first time you use them. Annealing these cases will reduce the stress in the cases from working them during the conversion process, making it possible to get decent life out of them.

I hold the case with my bare hand into the flame, rolling the case with my fingers to heat around it.

Lastly, brass will get brittle from age. At this point in time, there are lots of “old casings” floating around, as centerfire brass cased ammunition has been around since the late 1800s. If you have firearms in older, odd-ball calibers you probably have some of these. For that matter, .223 ammunition has been around for 60 years. But unlike .223, some of those older calibers have only had very small amounts of components (or none at all) for decades. Even if these cases are unfired, their age alone can be problematic. I’ve had old casings split the first time I’ve tried to reload them. Annealing them can make them usable. With even common components hard to get now, this can be really useful to reloaders.

The annealing process itself is fairly straightforward and simple. It is a heat-treatment process. You heat the brass up to critical temperature, 650-700 degrees, and quench it. This is obviously different than steel, where heating and quenching are done to harden it. Regardless the devil is in the details. You can’t heat the whole casing, because if you anneal the case head the case is ruined. You just want to get the neck and shoulder of the case. The other tricky part is that because the casing is by nature really thin, heat travels really quickly through it. Obviously, this makes it tricky to anneal the case without heating the case head excessively.

Short pistol cases aren’t really suitable using this method because they get too hot to hold before the neck is hot enough to anneal.

There are a few different ways to anneal cases. Currently, there are a number of annealing machines on the market. I’ve seen a few of them. If you want a consistent, perfectly even anneal, then you will want to get one of these machines. Unfortunately, you do have to pay for that. These machines can be expensive (if any of you reading this have a suggestion for an affordable option, please let me know in the comments), with some models I’ve seen being $800 or better. A less expensive option is by hand with Tempilaq (a temperature indicating liquid) and a torch. I’ve seen people speak pretty highly of this method, and it isn’t particularly expensive. The one thing I don’t like about it is that you need a specialized material to do it, that being the liquid. With the supply issues we’ve had with simple things in the last 18 months, I think the future availability of a necessary consumable is a consideration. In fact, I think it was unavailable when I first started looking at annealing my cases several months ago.

.222 cases before and after annealing

So I found an even simpler and cheaper method, that didn’t take any specialized equipment. Similar to the Tempilaq method, I anneal the cases by hand with a torch. But, I hold the cases by the case head in my bare hand while I heat them. As the case neck heats up, the heat travels down the case. When it gets too hot to hold, I drop it into a container of water. From my research, you don’t need to be concerned about overheating the case neck (as opposed to the case head, where this is a major problem). One other advantage here, aside from being inexpensive and simple, is that you’re not going to overheat the case head. It will feel too hot to hold onto well before the case head can overheat, because obviously “too hot to the touch” is a few hundred degrees below the critical temperature. This also makes this method “self-correcting” if you heat the case too much, but you still won’t overheat the case heads if you burn your hand (unless you’re trying to be a real trooper about it). As I heat the case, I roll it in my fingers to try to evenly heat the case all the way around. Obviously, this does not result in it being perfectly even all the way around, but it works fairly well with a little practice. When the case is ready, you drop it in the water to quench it, and then your cases are done.

After heating, I drop the cases into a container of water to quench them.

To illustrate this process, I annealed some old Turkish 8mm Mauser cases. Most of these cases weren’t properly annealed originally, and many times the case necks will split on the original firing of this ammunition. Some of you reading this are undoubtedly asking, “Why in the world would you bother to mess with those?” I started experimenting with annealing using them because if I ruined them, no great loss. Now that I figured out this process, I have a project in mind for them. I also annealed some .222 cases I’m using for a case conversion as they were similar to .223 in size, just to show that it works with smaller rifle cases as well.

 At any rate, I used a simple propane torch to heat the cases, and a container of water to quench them. That’s all you need for equipment for this quenching method. Obviously, you need to be careful to not stick your fingers directly into the flame. You could probably use a butane torch instead, which might be a little easier in that regard. It’s best to place your water so that you just drop the cases straight into it from the flame. That ensures that when you inevitably get the case a bit hot while you’re getting the hang of it, you’re not playing “hot potato” trying to get a piece of hot brass to the water. I also find it’s easier to “see your progress” as the case is heating if the cases are clean when you start. 

That looks reasonably close to annealing on factory ammunition.

Hopefully, this article sheds a little light on the process of annealing your cases, and its purpose. My method is a quick and easy way to try it out, though there are some other methods of annealing. Any way you do it, annealing your cases will give you a much longer case life. Until next time, happy loading!

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About the author: Christopher Mace Christopher Mace enlisted in the US Army as an Infantryman in 2001. He served in the 82nd & 101st Airborne Divisions, with four deployments to Afghanistan & Iraq. Chris started hobby gunsmithing in 2005. After completing his service in 2010, he earned AAS degrees in Machining as well as Welding & Fabrication, and a Gunsmithing Technician Certificate from Trinidad State Junior College. Chris has taken several armorers courses on different firearms, and has built several different types of firearms. He has been collecting & shooting military firearms, old and new since he was 18. Chris enjoys repairing, customizing, building & assembling firearms, as well as different disciplines of competition shooting.

{ 13 comments… add one }
  • Chris Mace May 17, 2022, 3:21 pm

    There is certainly more than one way to “skin this cat” so to speak. Each way has its own pros and cons. The method I described is perfectly safe if you employ some care while doing it. If you prefer to use another method, there’s nothing wrong with that. This is just a simple way to anneal brass, and how I anneal my brass presently. I have tried some of the other methods described by other folks here and didn’t really care for them. Your Mileage May Vary. Eventually I may purchase one of the annealing machines commercially available. They do seem to be nice.

    Contrary to popular belief, not all metals use the same methods of heat treatment. Some metals, like brass, use radically different procedures than steel-just as an example. However, metallurgy is beyond the scope of this particular article. From the amount of discussion on it here, perhaps I should consider writing about it and how it’s relevant to our hobby in the future.

  • Daryl Deuel May 17, 2022, 9:00 am

    The Annealez is a good relatively cheap machine to use, I’ve had good luck with it and it eliminates the risk of burning your fingers and heating too long.

  • bruce bowersmith May 16, 2022, 8:56 pm

    Chew yer damn fingernails much?

  • Ronn May 16, 2022, 5:29 pm

    Strictly speaking, the water quench is unnecessary for annealing.

  • Tom Evans May 16, 2022, 5:16 pm

    if you have ever touched something that has to go to templaq temperatures, (475F), you quickly learn that you dont want to accidentally discover what 2nd or 3rd degree burns are all about. not a good idea to do by hand, so dont do it!
    Tom at Enterprise Services LLC., has a really simple set up that comes with 2 torch heads, a cool stand to organize the cartridges, a bottle of templaq, and a spinning cartridge holder. excellent price compared to one burned finger and thumb….
    i also use an EP integrations rolling drum that is electronically controlled, just paint up a couple necks with Templaq to get the digital speed right,, put a metal cake pan under the drum, and 15 minutes later you have 100 cases done and you are off loading again.
    i like to hand load and without annealing, your favorite cases will show up cracked after work hardening them from firing.
    ALSO, always recap before annealing incase you have a hot primer. they will blow off a fingernail or worse yet, put hot exhaust debris in your face.
    annealing accurately pays off in spades if you take the time to do it right.
    if you are in a hurry, dont bother to anneal if you dont want to take the time and investment to do it well.
    also, go to Lowes and get a butane bottle refill rig that fits your grill’s bottle and refill your own. lots of youtube videos on that.
    BE SAFE.not foolish. hands off…..

  • Paul Ruffle May 16, 2022, 4:12 pm

    Holding the case with your fingers and heating the neck with a torch just looks like the wrong thing to do. It’s too easy to end up burning your fingers. Others here have listed much safer methods for annealing the neck without overheating the case head. I would use one of the alternate methods and suggest the author do the same.

    • M1A-Hole May 17, 2022, 9:55 am

      Link? Sources? Any Info?!?

  • Heath May 16, 2022, 1:59 pm

    I like the cake pan but if your doing hundreds it gets old. Annealez is a great product and easy to set up. With expensive cases I’ve really been able to extend the life of my brass. But if your only doing 50 at a time, the cake pan and water bath is a great proven technique.

  • seapeople May 16, 2022, 12:01 pm

    I use a drill motor with a 1/4 drive socket adapter and whichever size socket just fits over the outside of the case from the base. I zip tie the drill motor trigger to keep it engaged, and set at a slow to medium speed. I insert a cartridge into the socket, aim the propane torch at the head and neck and watch for the case colors to appear. The spinning cartridge keeps the heat even. Overheating the head is not possible if the torch is angled to the neck and attention is paid to watching the case colors work down the case from the shoulder. A quick nudge from a finger near the base of the cartridge will dislodge it from the socket, I drop it into a catch basin without water. Memory from high school metal shop says annealing is done by slowly cooling the metal. Fears of overheating the cartridge by doing this are nil as I’ve had hotter brass go down my shirt after shooting it.

  • jerry May 16, 2022, 11:34 am

    Like Joe, I stand mine up in a flat cake pan in about 3/4 inch of water. Spread them out so when you tip them into the water you don’t knock another case over. Spread out like that, you can just knock ’em over with the torch without bothering the next case.

    • Dr. Manarii Tane May 16, 2022, 1:08 pm

      This is exactly what I do. Just stand the empty case is 1/2 -3/4 inches of water and when it gets hot enough, just knock it over into the water to cool. Works great on my .30-06 hunting ammo.

  • Doug Lash May 16, 2022, 10:23 am

    Holding the cases by hand works ok for a small amount of brass. Say 20 or so cases. But hearing more cases than that will eventually lead to getting a burn on your finger tips as your fingers absorb some heat from each case.

    So I use a cheap electric screw driver with an appropriate sized deep socket on the shaft to hold and turn the brass. Select a socket that allows just the part of the case you want to anneal exposed.

    Use the hand method to anneal a couple of cases and watch the color that the case neck turns before you drop the case. Then anneal a case with the screwdriver while counting to see how long it takes for a turning case in the screwdriver reaches the same color. Then do the rest of the brass with the screwdriver heating each case the same amount of time.

    You can run this process for a couple of hours to handle a large amount of brass. I use a pair of cheap rechargeable screwdrivers from Harbor Freight for this. One is charging while the other is working. Not as convenient as using a specialized annealer, but much cheaper.

  • Joe Stubblefield May 16, 2022, 7:57 am

    ….or you can stand up your brass in a pan of water and aim flame down the spout and just knock it over when you see it heat up. No danger of overheating the head and no danger to the fingers.

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