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ANNEALING BPCR CASE NECKS
By Wayne McLerran
Updated 8/20/14

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
which 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 red 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
red.  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 450° unless
the cases are shorter than about 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 Case Neck 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)        Casting thermometer 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.  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.

Hand annealing using a propane torch
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.  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.
Notes:
- 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 simultaneously.

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 stamped 45-2.6
.

































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 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 indicating temperature.

Concerning annealing equipment, you can spend as little as a few dollars to
hand anneal or over $800 for a top-of-the-line carrousel-style annealer.  The
expensive carrousel-style 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 annealing equipment suppliers.


Annealing Equipment Suppliers:

Hand Annealing Kits:
By my way of thinking these are a solution to a nonexistent problem since a
drill, socket and a bottle of Tempilaq works just as well if not better.  
Note: Propane torch is not included.

Meacham Tool & Hardware, Inc., http://www.meachamrifles.com/
Similar to the Hornady solution below, Meacham sells “A Deal to Anneal” case
holder that mounts in a drill to spin and dump the case after the neck is properly
heated.
$15.00 + shipping.













Hornady, http://www.hornady.com/store/Annealing-System-1-Each/
Annealing System (Part # 041220) – Was available from Hornady, MidwayUSA
and other suppliers but has recently been discontinued by the manufacturer.
The Hornady annealing kit only came with a bottle of 475° Tempilaq and
suggests using it just below the case neck, even for long rifle cases, which I
disagree with.  475º Tempilaq is excellent for ensuring the case base is not
annealed, but is definitely not useful as an indicator of the correct neck
annealing temperature.  Heating the necks to only 500° or so does not result in
adequate annealing.  And, although the kit contained three sizes of case holders
to use in a drill, none are large enough in diameter to use with .45-70 or similar
cases with the same diameter base.  But since the holders were made out of
aluminum, it’s easy to drill out one to increase the diameter.  But why go to the
expense ($52 at MidwayUSA) and trouble when a 5/8” socket works just as
well and a bottle of 750° Tempilaq can be purchased from Brownells or
MidwayUSA for less than $22.














Enterprise Services, LLC, http://www.cartridgeanneal.com/
Anneal-Rite II Cartridge Case Annealing Unit.  Comes with three stands and one
case holder.
$98.00 + shipping.  Holders for other calibers are $20 to $37.















The Woodchuck Den, http://www.woodchuckden.com/
The Woodchuck Den has been 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’s a neat tool that attaches 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.  The current price is $51.95.













Carrousel-style 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 not included.

Ballistic Edge Manufacturing, http://www.annealingmachines.com/
MODEL 360 ($395.00 + shipping) - Constructed of zinc-plated welded-steel &
features a one-size fits-all rotating case drive wheel.  
The cases do not spin as
they are being rotated or heated.
 Very similar to the Brass-O-Matic, which is
no longer manufactured.
MODEL 400 ($495.00 + shipping) – Precision machined from aluminum &
features a rotating shell-plate custom made for your choice of up to 4 sets of
hole sizes.  
The cases spin as they are being rotated and heated.













Grizzly Gunworks, http://shop.grizzlygunworks.com/Rifle-Shell-Case-Annealer-
GGW2ANNEALER.htm
The shell plate is custom made to accommodate up to 4 sets of hole sizes.  All
calibers are available up to 50 BMG.  
The cases spin as they are being rotated
and heated.
$799.00 + approximately $40.00 shipping depending on location.



















Ken Light Manufacturing, http://www.kenlightmfg.com/products.html
BC 1000 Automatic Case Annealer comes complete with one cartridge head
wheel. Additional wheels are available for a fee.  
The cases spin as they are
being rotated and heated.
 The designer and owner is Ken Light.
$475.00 + $45.00 shipping















Bench-Source (Vertex Manufacturing), http://www.bench-source.com/id81.
html
The model 10G107 shell plate fits up to the largest magnum cases & can be
supplied for .50 BMG caliber.  
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.
$499.95 + $22.50 shipping
Note: Buffalo Arms (
www.buffaloarms.com) now sells the Bench-Source unit
for $510.00 + shipping.

After considering the other brands, 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.


















Zephyr Dynamics, The Brass-O-Matic is no longer manufactured.  Refer to the
Ballistic Edge Manufacturing Model 360 for a very similar unit.


Wishing you great shooting,
Wayne