Most shooters are aware that brass work hardens as it is fired in a rifle and sized in a die. The work hardening process makes the brass harder and less ductile. If you have ever bent a piece of solid copper wire back and forth repeatedly, you’ll notice it breaks. This is an example of the soft ductile copper work hardening (and why extension cords use braided wire). When the case expands and then contracts in a rifle chamber, or is resized as part of the reloading process, it is work hardened. Work hardened brass in a rifle can manifest itself with the appearance of split necks, increased chamber pressure, inconsistent neck tension and poor accuracy in cases that are repeatedly reloaded. This is one of the many reasons reloaders track the number of firings on a given case. (Note: for a material sciences explanation of annealing, please see The Science of Cartridge Brass Annealing).
One way to avoid work hardened brass is to mitigate the work hardening process. For instance, using a traditional full length or neck sizing die during the reloading process works the brass twice, once when the case neck is sized down (and shoulder depending on how the die is adjusted) and again when the expander passes back up through the neck. A bushing die without an expander works the brass less, and in my experience as well as others, provides more case life (I’ve notice far fewer cracked necks since I adopted bushing dies). The bushing are available in .001″ increments and when the proper size is selected, the brass isn’t worked more that it is needed for the operation.
Another area to avoid work hardening brass is only setting shoulder back too far. It is common for new reloader to set back the shoulder more than necessary, causing the brass to stretch in the chamber and over time, potentially leading to a dangerous condition known as case head separation.
Annealing is a process that heats the brass case to make it softer and more ductile, effectively reversing the work hardening process. All brass is annealed as part of the manufacturing process. On many brass cases you’ll notice the telltale discoloring around the neck shoulder junction (if you don’t see it on a new case that just means it was polished away). In the image below, note the discoloration around the neck and shoulder, evidence of factory annealing on the 300 BLK brass.
Over the last two decades of reloading, I’ve heard the benefits of annealing debated to great extent. One of the best experiments I’ve found of the annealing process was conducted by Col. Art Alphin. In “Any Shot You Want: The A-Sqaure Handloading and Rifle Manual”, Alphin uses pressure testing equipment to compare the annealed versus non annealed cases with the same 30-06 load over five firings. His annealed cases do not show a noticed able increase in pressure, however, his non annealed cases l show an increase of 8,400 PSI! This is telling.
A quick note: this post isn’t a how to guide on annealing, rather an overview of the process and review of an annealing machine. Improper technique during the annealing process can result in unsafe cases that can cause death or serious injury.
Traditionally, annealing was accomplished by placing the case in a pan of water, heating the neck with a small torch and tipping the case over when the neck was the proper temperature. The water served as a heat sink for the bottom of the case, which you do not want to soften. The problem with this method was it yielded inconsistent results. Back in the 90s my good friend made a few unsuccessful attempts to use this method to anneal his brass after reading “Any Shot You Want”. He still refers to it as witchcraft that ruined his brass and is bitter about it to this day (and I’m still laughing).
Unhappy with the water pan technique, forward thinking shooters developed what was known as the “socket method”. A deep well socket was selected that would cover the majority of the case body. It was chucked in a drill and spun with the case neck exposed to a torch. This method provided even heat to the neck, but still wasn’t as consistent as many would like.
In recent years annealing machines have arrived on the shooting market. These machines use a torch or induction heater to provide an even heat to the case neck and shoulder area. The speed and consistency in annealing process is a far cry above the traditional methods. One of these machines is the Annealeez (shown above).
The Annealeez is annealer that uses a propane torch to provide an even heat on case necks. The machine is fully adjustable to work with cartridges as small as 221 Fireball or 300 BLK and as large as 50 BMG!
Setting up the Annealeez is fairly simple and straight forward. Screw a bottle of propane onto the hose and adjust the torch and dwell time of the cases and you are done. Jeff Buck, owner of Annealeez has created a series of instruction videos on how to use the machine and anneal brass. He includes guidance on how to properly anneal cases (if you look at the graph in The Science of Cartridge Brass Annealing you’ll see under annealing doesn’t do anything- over annealing is unsafe). After some reading, I decided to use Tempilaq, a heat indicating paint, to adjust the amount of heat on the case since I had it on hand.
Once the machine is set up, the brass is deprimed, cleaned and fed into the hopper. A wheel picks up a case to feed into the flame, while another wheel rotates the case allowing even distribution of heat. After the case is in the flame for a predetermined time adjusted by the user, the case is dropped into a pan and a new case if fed in. Very easy. Since I am not going to go into detail on setting up the machine, take a look at this YouTube video:
Running a batch of brass is extremely straight forward, just load the deprimed cases (loaded or primed cases would be REALLY BAD) into the hopper and watch the magic. The machine runs off of a standard 110 volt plug and a 1 pound cylinder or propane (mine cost $4.95 at the local hardware store). According to the manufacturer, one pound of propane should be sufficient for 2,000 cases.
Before we get into the good stuff, take time to read our disclaimer: WARNING: The loads shown are for informational purposes only. They are only safe in the rifle shown and may not be safe in yours. Consult appropriate load manuals prior to developing your own handloads. Rifleshooter.com and its authors, do not assume any responsibility, directly or indirectly for the safety of the readers attempting to follow any instructions or perform any of the tasks shown, or the use or misuse of any information contained herein, on this websi
Annealed brass in hand, I decided some sort of test was in order. I don’t have the fancy equipment Art Alphin and A-Square had to pressure test annealed versus non annealed, cases, but I did have a rifle and brass.
As noted above, all of these cases have been neck sized only in with a Redding Competition Match bushing die without an expander ball.
I decided to compare the annealed versus non annealed brass in a 308 Winchester. I loaded up some Federal brass that was fired three times with 175 grain Serra MatchKings (SMK) over 42 grains of IMR 4064 and a Wolf large rifle primer. Cartridge overall length was 2.808″.
The test gun was my custom Savage Axis HB in 308 Winchester. No longer the $285 (after rebate) rifle I scored at my dealer, this bad boy is tricked out. I sourced the MDT LSS and Timney trigger direct from the manufacturers. The other parts came from Brownells. Let’s look at the cost break down less rings, bipod and optic (prices are April 2016):
- Rifle $285
- Scope base $11
- LSS FDE Cerakote $399
- CTR stock $57
- CTR riser $19
- Extension tube and nut $26
- Pistol grip $19
- Timney trigger $112
Total cost $928. If you are recycling some parts from your AR or buy some of the items used, you’ll save even more. While $928 puts you at a price point on par with a Remington 700 or a well equipped Savage 10, those rifles aren’t running a customizable chassis system with an AICS style magazine. Street price in my area for a Ruger Precision Rifle is $1299 plus tax, this custom Axis is nearly $400 cheaper. Build one of these and you have a lot of money left over to invest into optics, ammunition, or buy an annealing machine.
A look at the annealed (right) and non annealed (left) hand loads. Note the discoloration from the annealing process. The photograph doesn’t do the discoloration justice, in person, it is much more noticeable.
To test the loads, I shot the rifle prone, from a bipod with rear bag. The targets were 2″ orange dots at 100 yards. Velocity data was recorded with a MagnetoSpeed barrel mounted ballistic chronograph.
I fired three, 5 shot groups of the annealed and non annealed brass loads. The annealed brass loads are shown above, in the top row. The non annealed loads are shown in the bottom row. Average group size for the annealed brass loads was .743″, average group size for the non annealed loads was .835″. The annealed loads had an average group size 11% smaller than the non annealed loads.
Average velocity for the annealed load was 2551 feet/second with a standard deviation of 17.1. Average velocity of the non annealed load was 2567 feet/second with a standard deviation of 22.2.
In my testing, average group size was smaller for reloads using the annealed brass than those using non annealed brass. Lower velocities and standard deviations were recorded in the annealed loads. A note on sample size- my sample size was small, I note this as a fact and plan on conducting further tests with more groups in the future.
I plan on annealing as part of my reloading process in the future. I know quite a few high volume match shooters who anneal, but those aren’t the only shooters who can benefit from annealing, wildcatters and improved cartridge shooters can benefit as well. A few months back I built a 257 Improved hunting rifle. 257 Roberts brass is difficult to find, expensive when you do, and the fire forming process work harden the brass. Annealing the cases to extend the brass life for a cartridge like this is cheap insurance.
If you are considering annealing your brass to decrease pressure and increase case life and accuracy, the Annealeez is a great machine. To learn more about annealing brass or the Annealeez, click here.