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|ANNEALING BPCR CASE NECKS
By Wayne McLerran
Annealing is essentially the opposite of hardening. Steel is hardened by
raising its temperature to a range that allows the grain structure to be
altered, which is then “frozen” by quenching (rapid cooling). If the
steel is reheated to a high temperature and allowed to slowly cool it
will be annealed or softened. Steel can be hardened or softened by
using heat but brass is different and can only be hardened by “work-
hardening” (stressing the grain structure) and only softened by applying
heat. Reforming, resizing and simply shooting will work harden
cartridge brass. By the way, if you hear or read that quenching hot
brass will harden it, don’t believe it and question anything else from
the same source.
Prior to annealing BPCR cases, I had “hand annealed” high power
smokeless bottleneck case necks and shoulders. The smokeless
bottleneck cases were annealed to eliminate neck and shoulder case-
hardening resulting from full-length resizing after repeated firings.
Annealing is also commonly utilized to soften case necks and shoulders
when reforming (converting) brass to use for a different cartridge.
Since I use fire-formed straight-wall BPCR cases and finger seat (slip-
fit) bullets with very little or no neck tension I’d never considered that
annealing the necks was beneficial. But during BPCR reloading
discussions with a very experienced shooter, he convinced me to try
annealing. He’d experienced some problems with his reloads several
years ago. He was seating the bullets with neck tension and did some
testing indicating the problem was variations in neck hardness which
annealing will eliminate. But at the time he didn’t believe annealing
was necessary with slip-fit bullets. Later, additional testing confirmed
that variations in neck tensions, even with slip-fit bullets, directly
resulted in measureable changes in muzzle velocity and bullet impact
vertical dispersion. After annealing the variation disappeared and
accuracy improved. Although finger-seated bullets are loaded without
significant neck tension, when fired and obturation occurs, annealing
will help mitigate the negative effects of inconsistent bullet release
due to hard necks.
After annealing a large number of used cases for the 1st time, a neck
expander was used to check the neck ID of the fire-formed cases. The
slight resistance felt with the expander was very uniform and
consistent from case to case. Prior to annealing, even after using the
neck expander, the resistance varied from case to case, which was also
felt when finger seating bullets. Many BPCR shooters reload with some
neck tension and annealing is recommended on a regular basis. Some
experienced shooters anneal after each firing as a normal part of their
reloading process. Annealing is also recommended when initially using
Starline brass, which has the reputation of being harder than
Remington or Winchester brass. Another sign that annealing is needed
is when cases come out of the chamber with dirty necks indicating the
brass did not expand sufficiently or fast enough to seal out gas and
fouling blow-by or blow-back. Finally, if accuracy falls off for no
apparent reason after firing the cases a few times than annealing may
be in order.
Various techniques have been used to anneal brass while protecting the
case head, including but certainly not limited to the following. Dipping
the necks in oil then for a few seconds in 800°F melted lead. Standing
the cases up in a pan of water with the necks above the water, then
heating with a torch until the necks turn blue and tipping the case over
in the water to cool. Holding and turning the case with pliers or an
electric drill with the neck in the flame of a torch then dropping the
case in a pan of water. Anneal until the necks glow red will result in
damaged brass because the temperature is well above the annealing
range and the brass becomes too soft. Annealing in a dark room until
the neck shows the 1st hint of glowing orange is a much better
approach and should work fine, but can result in overheating the brass
if you’re not careful and paying close attention. The cases should be
rotated and the necks heated with a propane torch. Use a drill and
hold the case in a standard socket slightly larger than the case. Stop
heating when the case neck shows the 1st hint of glowing orange. You
can dump them on a wet towel or in water to speed up the cooling
process but it's not necessary. Quickly cooling brass will not harden it
as it does other metals.
Cartridge brass can be annealed at temperatures as low as 480° to
490°F but will require an extended time (hours) to fully anneal. Even
at 600° it may take an hour or more and the complete case would be
annealed, not just the neck, resulting in a very unsafe condition. If the
head is annealed even slightly, it can fail and blow apart when fired.
The solution is to quickly raise the temperature in only the neck area
to a range of 700° to 800°F, at which point the neck is fully annealed.
Since the high temperature is only applied for a very short duration,
typically 3 to 4 seconds, the case heads will not exceed 480° unless the
cases are shorter than about 1.5” to 1.75”. By the way, YouTube has
several videos on annealing. But be aware, some are clearly
misleading and can result in damaging the brass due to overheating.
Hot Sand Annealing
What you will need:
1) Some clean playground sand.
2) A stove and pot to heat the sand. One of the Lee Precision
electric casting pots is an ideal solution.
3) A Casting thermometer or digital meter with a thermocouple is
used to check the sand temperature
4) Some type of small simple metal stand to place in the pot and
cover with sand to the depth of the case necks. One solution is to
bend a piece of sheet metal to fit.
You’ll need to experiment to find the preferred temperature, which
will likely be
around 800°F to 950°F. Once the sand is heated to the desired
temperature, stick a case neck down into the sand until it hits the
metal stand. Stick another case in the sand and remove the 1st one.
Increase the heat if the necks are not getting sufficiently hot as
indicated by a subtle color change. Do not leave the cases in very long
or the entire case will become annealed and soft, resulting in an
unsafe condition when the resulting cartridge is fired.
Salt Bath Annealing
Very similar to hot sand annealing, but rather than sand the process
typically uses a mix of Potassium Nitrate and Sodium Nitrite (both are
salts). As when hot sand annealing, the salts are melted and held to
temperatures in the range of 800°F to 950°F, which are considered
low temperatures when heat treating metals. Here’s an excellent
video on the process: https://www.youtube.com/watch?
What is required:
1) 1 to 2 lbs of Low Temperature salts.
2) A stove and pot to heat the salts. One of the Lee Precision
electric casting pots is an ideal solution.
3) A Casting thermometer or digital meter with a thermocouple is
used to check the sand temperature.
4) A fixture to partly immerse in the melted salts which will hold
cases neck down and allow easy hand insertion and removal.
Suppliers of annealing salts and salt bath annealing kits are listed
below under Annealing Equipment Suppliers.
Hand annealing using a propane torch
Prior to purchasing a semi-automatic annealer, the hand annealing
process I used consisted of heating the neck of a slowly rotating case
with a propane torch in a brightly lit room. The cases were inserted
into and rotated with a standard ½” drive 5/8” socket using an
electric hand drill. Here’s a similar process: https://www.youtube.
com/watch?v=kgD5D0Wzu-c. To ensure the necks reached the correct
temperature and were not overheated, Tempilaq, a temperature
indicating fluid was used. 750° Tempilaq was applied inside the case
necks of a few cases to determine the amount of time to hold the
rotating case necks in the torch flame. Once applied it quickly dries.
When the Tempilaq temperature is reached it liquefies and typically
changes color. When 750° Tempilaq liquefies it changes from a light or
medium blue to a dark grayish blue. If it gets very dark or black than
you’ve overheated the brass. Once the correct heating duration was
determined, Tempilaq was not used with the rest of the cases. By the
way, applying 750° Tempilaq to the inside of the case necks was found
to be more accurate than applying 650° Tempilaq to the outside of the
case just below the necks. After annealing, the case was dumped out
of the socket onto a soft towel. Quenching the hot case in water does
not affect the annealing process and will not harden the brass.
- 750° Tempilaq is very thin and wiping several layers or dabbing it on
will normally be required to build up an adequate light blue layer.
Fortunately it dries quickly. After heating the grayish dark residue
should dissolve with water if it was not overheated and baked on.
- Per the factory, when using any temperature range of Tempilaq, the
key is when it liquefies; not the color change although it should happen
I use Remington cases which are normally annealed shortly after being
cleaned in a tumbler with ceramic media. Prior to annealing they are
“sparkling” clean inside and out. What I found interesting is when the
correct temperature was reached the color change in the necks was
very subtle. They did not turn a deep blue or display the vivid colors
seen in some photos of annealed brass and in a few of the YouTube
videos. It is my opinion that the vivid colors are a result of over-
heating the necks or possibly due to oxidizing of the case surface from
aging. The following photo displays the before and after annealing
results of brand new Remington, Winchester and Starline brass and is
similar to the color change of freshly cleaned brass. The brass was
annealed using a carrousel-style semiautomatic annealer. Although
listed as .45-90, the head of the Starline case to the right is actually
Damage from over annealing
So what happens if the brass is over-annealed (over-heated)? Damage
can result because the brass becomes too soft and hardness can only be
restored by work-hardening. Bottleneck case shoulders can collapse
when seating bullets with neck tension and the cases can be harder to
extract for the same reason mentioned below for straight wall cases.
As long as the base is not annealed, over-annealing the neck is not a
dangerous condition but can lead to case extraction problems, case
stretching and eventually separation. If the case neck and/or body are
too soft the brass will not spring back as much after firing, possibly
resulting in “sticky” extraction. The soft brass also has an increased
tendency to stretch and will require trimming. Repeated stretching and
trimming can eventually lead to case separation. Too soft case necks
are also reported to result in less accurate loads, the opposite of what
proper annealing is meant to fix.
Although I shoot slip-fitted (finger seated) bullets, based on the uniform
neck tension results after annealing, which was very consistent from
case to case, I plan on continuing to anneal after each firing and will be
using a carrousel-style annealer. By the way, if you plan to anneal short
cases less than 1.75”, I highly recommend applying 475° Tempilaq to
the base area to ensure the base does not become annealed and quickly
dump the cases in cold water to stop the heat from reaching the head.
475° Tempilaq is cream colored and turns clear when it melts at the
Concerning annealing equipment, prior to recent developments using
induction heating one could spend as little as a few dollars to hand
anneal or over $800 for a top-of-the-line carrousel-style propane-based
annealer. Induction heating is the newest technology being applied to
annealing cartridge cases. It’s fast & precise but, with prices up to
around $1,100.00, the technology is not cheap. Included in the
equipment listed below are four induction units dedicated to case
annealing. The expensive units, either propane or induction based, do
not guarantee a better result but do provide a level of control and
faster processing rate not available with hand annealing solutions.
Following is a list of case annealing equipment suppliers.
Annealing Equipment Suppliers:
Hand Propane Annealing Kits:
By my way of thinking these are a solution to a nonexistent problem
since a drill & socket, which you likely already have, and a bottle of
Tempilaq works just as well if not better.
Note: A propane torch is not included with the following solutions.
Although no longer available, the Meacham Tool & Hardware, Inc. sold
the “A Deal to Anneal” case holder that mounts in a drill to spin and
dump the case after the neck is properly heated.
Although no longer available, The Woodchuck Den was selling the Series
II Annealing Tool, also known as “The Ring of Fire” for several years to
bench rest and varmint shooters to increase the accuracy potential of
their ammo. It was a neat tool that attached to a Bernzomatic torch
for uniform neck annealing without the need to rotate the case. You
can either hold the cases individually with pliers or stand them up in a
flat pan with the bases covered with water.
Salt Bath Annealing Kits & Supplies
High Temperature Tools & Refractory
A supplier of annealing salts.
Salt bath annealing kits and supplies.
Automatic Propane Torch-based Annealers:
These are certainly expensive but provide a level of control and faster
processing rate not available with hand annealing solutions. Note:
Propane torches are typically not included.
Giraud Case Annealer (Giraud Tool Company, Inc
Designed for volume annealing, using a propane torch assembly, the
automatic case feeder can handle several hundred .17 cal. to .50 cal.
cases at a time by only changing the feeder wheel disc and transfer
plate, a 2-minute task. See the unit in action at
Somewhat similar to the larger volume and more expensive Giraud Case
Annealer, but on a smaller scale, the Annealeez annealer is an
economical solution designed to automatically process a large number
of cases. The standard unit will handle .223 to .30-06 cases. Optional
indexing wheel kits are available that can handle cartridges
as small as 17 hornets and as large as 338 Lapua Magnums. The
simplicity of the design and price is appealing and this is the unit I
would purchase now if I did not already own the Vertex Bench-Source
annealer discussed below. To view the Annealeez in action and other
related videos, go to:
Sagebrush Annealer The Sagebrush annealer is a simpler design and
does appear to do the job. The one disadvantage, and I consider it a
major shortcoming, is the inability to control speed. The only heating
control is the torch position & flame adjustments, which is a drawback
when setting it up for different cartridges. If you've tried to precisely
adjust the flame of a propane torch you know what I mean.
Bench-Source Annealer (Vertex Manufacturing)
The model comes with a shell or carrier plate that fits up to the largest
magnum cases. It can be ordered for .50 BMG caliber or later
upgraded with a .50 caliber carrier plate. Using a different technique
than the other brands, the shell plate stops and the case spins while
being heated. Although the unit is setup to use two torches, only one
is generally necessary due to the unique design. The designer and
owner is David Dorris.
Note: Buffalo Arms and Graf & Sons now sell the Bench-Source unit.
After considering the other brands available at the time, this is the unit
I purchased and highly recommend. The design is well thought-out and
the construction is excellent. It has all the features required plus
some; comes with an excellent user’s manual and is comparatively
priced. By the way, the carrier plates shipped with the current units
have an additional set of smaller holes in line with the larger holes
which are not displayed in the photo below. They are for smaller cases
such as .223, .222, Fireballs, Hornets, Bees etc. And for those of you
that are curious as I was, the very small holes closer in to the center in
the photo below are used for manufacturing, not for very small cases.
Here’s a good video on the unit:
Home Made Annealer
For those of you that are handy making stuff, see the following
YouTube video link for the details on how to make a nice unit for $100
or less: https://www.youtube.com/watch?v=k0xE-6bSwME
Here’re some examples of prototype propane torch-based automatic
Utilizing the same technology used in electromagnetic induction heating
kitchen cooktops, induction brass cartridge case annealers are a
relatively recent development. Currently they are more expensive than
propane torch-based annealers, but offer some benefits. By controlling
the power and timing, very precise and repeatable temperatures can
be applied to each case neck, eliminating the risk of overheating the
Annealing Made Perfect (AMP) Induction Annealer
The unit was announced at the 2015 SHOT Show. Currently at a retail
price of $1,099.99 plus shipping from Graf & Sons, the USA distributor
& reloading equipment supplier. Each case is hand inserted using the
correct pilot and standard shell holder.
Annie Induction Annealer (Fluxeon)
With over 1000 watts of induction heating power, a typical case can be
annealed in around 3 seconds. Cases are inserted by hand. The unit is
currently priced at $484.00 + shipping.
AGS Brass Annealer
Made in Serbia, the AGS annealer is the new guy on the block with a
nice reasonably priced unit. At 6” X 6” its footprint is the smallest of
all the semi-automatic annealers. Included are two sets of
interchangeable inserts for different size brass. The website indicates
it’s powered by a Wall charger – 12V DC 5.5mm – 2.1mm, 2A, but the
power cord is not included due to differences in outlet configurations.
I assume the comment is due to differences in USA and international
outlets. Following are a couple of YouTube videos showing the unit in
operation: https://www.youtube.com/watch?v=v2BtAG0RqRw, https: