Annealing is a process wherein heat is applied to a metal in order to
change it's internal structure in such a way that the metal will become softer.
Most of us think of "heat treating" when we think of applying
heat to a metal in order to change it's internal structural properties. The word
"heat treating" is most commonly associated with steel. However, the term heat
treating is not annealing, except in a general and journalistic sense of
the word. Heat treating refers to a process wherein the metal is made
always means to make the metal softer.
In order to make steel harder, it is heated to some temperature,
and then cooled fairly rapidly, although this is not always the case. Brass, on
the other hand, cannot be made harder by heating it -- ever -- brass is always
made softer by heating.
The only way brass can be made harder is to "work" it. That is,
the brass must be bent, hammered, shaped or otherwise formed. Once it has been
made hard, it can be returned to it's "soft" state by annealing. The hardness of
brass can be controlled by annealing for a specified
time and temperature.
BC-1000 Cartridge Case
The After Market
Ken Light Mfg.
PO Box 2745
Lake Havasu City, Arizona 86405
BC 1000 w/357 Magnum Shell
Unlike steel, which will be made harder when it is cooled
rapidly, brass is virtually unaffected when it is rapidly cooled. Annealing
brass and suddenly quenching it in water will have no measurable effect on the
brass. Cartridge cases are made of brass. When cartridge cases have been
reloaded a number of times, the case necks become harder. Annealing will return
the cartridge case necks to their factory original state.
Cartridge Case Annealing
"Properly" annealed cartridge cases are essential
to maintaining accuracy and long case life when using handloaded
ammunition. The question is, what is "properly" annealed? What does annealing
do? Can a cartridge case be over annealed? What part of the case should
be annealed? Can annealing a cartridge case make it dangerous? Below, you will
find the answers to these questions, as well as a number of other questions that
you didn't ask.
A great deal has been written about cartridge case
annealing in the popular gun press. A great deal of what has been written about
annealing is misleading, with one exception: articles and books by Dean A. Grennell. In his "The ABC's of Reloading" (page 190), Mr. Grennell correctly
describes the procedure. Although it is a very short description, it is correct.
There is one slight error of fact, but it is on the side of safety and Mr.
Grennell cannot be faulted for this in any way. In fact, if you do not have this
book I recommend it -- even for "experienced" handloaders. There is much
valuable information in it, much of it overlooked in other publications. The
photo's are profuse and excellent, the explanation clear and concise, and the
writing is witty and wry.
After wading through this weighty tome, you will
know more about annealing and cartridge brass than you probably bargained for.
Few handloaders ever bother to anneal their brass.
The few that do are usually dyed-in-the-wool "gun cranks" (to use a rather
archaic term from the 1940's), "crazy experimenters" or shooters who are
involved in some form of competitive shooting. There is good reason for this,
too -- until now, annealing cartridge brass was, at best, a spotty proposition.
The brass is either over annealed, under annealed, improperly annealed or some
combination of all three. Annealing brass is time consuming, and for the most
part, the damn stuff doesn't seem to shoot any better than before it was
annealed. Sure, the brass lasts longer, but it does not seem to make any
improvements in accuracy. If anything, it might seem to open up groups. So much
for the way you used to think about annealing.
Now let's find out about doing it right. Not only
will annealing make the brass last up to 10 times longer, but it will tighten up
those groups too.
Before I go into the why's and whereof of cartridge
brass and the right way to anneal, let's review the traditional methods of
annealing, the attendant disaster, and how they occur.
The "Old Methods"
The usual procedure is to get a pan, something like
a cookie pan, and place enough water water in the bottom of it to cover the
lower one-third to one-half of the brass. Next the cartridges are stood on their
bases in the water. A flame from a propane torch is played over the case necks
until the brass "just begins to glow" or "just before it begins to glow". When
the magic moment is reached, the annealing is abruptly arrested by knocking over
the heated case into the water. The fact that the case neck is heated unevenly
and the case-to-case heating is hardly uniform doesn't seem to get much notice.
The reason for the water is that the
the cases must not be annealed, or even heated to any appreciable amount,
for reasons you will learn about later on.
Another method is to dip the case mouths into
molten lead that is at the "correct temperature. Of coarse, there are the
problems of lead sticking to the case (soldering), holding the case, and
preventing the base from becoming over heated. This process is obviously one for
Superman: he could hold the case with his fingers of steel and freeze the base
by blowing his supersonic breath over it.
Quite frankly, I have never seen anyone use the
lead pot method of annealing although I have read many articles describing it. I
think I can see why it is not a popular method. The next method is described by
Earl Naramore in his "Principles and Practices of Loading Ammunition" (circa
cases are polished and then placed on a small block of wood or metal. The
case is placed on the platform and a flame from a suitable torch is played
over the neck as the block is turned. This continues until the brass has a
slight color change, and then the flame is removed. The flame must be hot
enough so that the neck is heated sufficiently fast enough to prevent the
base from heating to a critical point.
Needless to say, this procedure will work fairly
well, but requires a high degree of skill. It is also very S-L-O-W! Can you
imagine having to anneal several hundred cases using this method? Another
drawback to this method is that you will have a decided lack of uniformity on
the periphery of the case neck, and the case-to-case results will be even less
uniform. So much for the "old methods".
Our present day cartridge cases represent over one
hundred years of continued development and refinement. Cartridge cases are
manufactured to exacting standards and tolerances from brass made especially for
A cartridge case starts life as a strip of brass.
It goes through a number of processes on it's way from brass strip to finished
cartridge case. It is punched, heated, cooled, cupped, washed, drawn, annealed,
formed, "upset" and trimmed and polished, though not necessarily in that order,
and I have left out a significant number of steps. Suffice it to say, the
manufacture of cartridge brass is involved and exacting. What we get is truly a
marvel of manufacturing magic.
Cartridge brass is annealed several times during
the manufacturing process. Each step is carefully controlled, and the brass is
tested and examined with sophisticated equipment.
As delivered, a cartridge case has a number of
properties especially suited for the job it must perform. Most shooters think of
the cartridge case merely as a convenient way of keeping the bullet, primer and
powder from getting all mixed up and a handy way of stuffing them all into the
gun in the proper sequence. As Rodney Dangerfield might say, "It don't get no
The Cartridge Case Inside The Gun
Actually, a cartridge case is the
component with which we have to deal in handloading ! Not only that, but it is
the cartridge case which seals the chamber when the gun is fired. If it weren't
for the amazing ability properties of the cartridge case, you would get a hot
blast of gas in your face every time you pulled the trigger.
After the trigger is pulled, the powder is ignited
and creates gas pressure inside the case. Under pressure, the case expands. The
outer walls of the cartridge case press against the walls of the chamber. As the
pressure builds up (as high as 55,000 pounds per square inch or more in a
rifle), the outer walls of the case press tighter and tighter. The more
pressure, the better the seal (up to a point, of coarse). The primer, held
securely at it's outer walls by the same pressure, and pressing against the bolt
face (assuming we're still talking about a rifle), does it's part to seal the
breach, even though it's primary job is completed by this time.
As the bullet speeds down the bore, the pressure
begins to drop. Finally, the bullet clears the muzzle and the pressure abruptly
drops to zero (in fact, to atmospheric pressure). The cartridge case, having
done it's job to seal the chamber, has more "work" to do. It must spring away
from the chamber walls so it may be extracted. If it does not, it will be a
bi___ to remove from the gun. If it fails to spring back from the chamber
walls sufficiently, it will seem to be a little "sticky". If it does not spring
back at all, it will take the hot hammers of hell to remove it.
In order for the cartridge case to perform it's
tricky tasks again and again, it must have it's properties restored from time to
time. One of these properties is it's physical dimensions. These are restored
each time the case is resized. When a cartridge case is full-length resized,
every dimension except the overall case length is restored. Principally, the
diameters of the case and the case's shoulder are restored.
Sometimes only the case neck is resized to original
factory dimensions. This is due to the fact the cartridge brass has a certain
resiliency and is able to spring back to a size which approximates it's original
size. It will still fit into the chamber of the gun it was fired in, but it may
not fit in another gun, which to all intents and purposes is "identical" in
every respect, except that it's chamber may be slightly smaller. As long as the
cartridges are used in the same gun after each neck sizing, no trouble will be
encountered. Ammunition loaded from brass which has been neck sized only, may
group appreciably tighter. I say may, because there are so many variables that
only you can determine which is the best combination of components, processes
and techniques for your gun.
Each time the case is fired and reloaded, changes
occur in it's structure. Except for the obvious changes in dimensions, these
changes are not discernable to the "naked-eye". The important changes occur at
the molecular level in the brass itself.
Properties of Cartridge Cases
A finished cartridge case is made so that the
hardness of the metal varies over it's length. It must be "hard" in some places
and "soft" in others. In order to make brass hard, it must be "worked" or, in a
crude sense, "hammered".
Most metals "work harden" as they are formed, and
brass is no different. The term "work" means that the fine granular structure of
the metal is placed under stress and changes as a result of forming or shaping.
These stresses remain in the metal in the form of changes to it's grain
structure. (This is somewhat oversimplified, but is accurate as far as it goes).
The metallic "grains" can actually be seen if the
brass is etched in an acid solution and examined under a microscope with the
proper lighting conditions -- obviously a laboratory job, and not a subject
which I will take up here. When the grains become too fine, the metal will
easily crack. However, there are ways to discern the general condition of the
metals structure without a laboratory examination.
The cartridge case, as it comes from the factory,
is not one single hardness over it's entire length. The neck, which must hold
the bullet in place with sufficient holding power to prevent it's setback while
undergoing recoil (as it is stored in a magazine or clip), is somewhat "soft"
compared to the head of the case.
By "soft" I do not mean to imply that it is like
"dough" or soft like an aluminum beer can. It is "soft" only in comparison to
the head of the case. On the other hand, the head of the case is not "hard" like
a ball bearing is hard -- it is only "hard" enough to do it's job and no more.
If it is too hard or soft, in the wrong places, the cartridge case will fail,
and your first indication of this disaster may be a cloud of gun parts flying in
into your face. Such a rapid disassembly of a gun is usually attributed to "an
overloaded cartridge," but just as well be from a normally loaded
cartridge (developing normal pressures) whose case failed rather
catastrophically, and, I might add, rather suddenly, because it had lost it's
How hard is "hard", and how "soft" is "soft"? It is
not a question which is easily answered, and I will waffle a bit during the
explanation. Normally you will use a cartridge case until it is no longer
serviceable because of two main reasons: the case necks will become too thin
from repeated sizing and trimming operations, or the necks start splitting. In
the first case, you will probably detect the thinning by simply looking at the
case necks. Your experience will tell you that they are not "right" and that it
is time to get a new batch of brass. In the second case, you will spot the split
necks as soon as they are extracted from the gun, or possibly during some
inspection step during reloading.
If there are only a couple of splits in a batch of
brass, you will begin watching it closely (as the neck splits are not
particularly dangerous) and occasionally (and unconsciously) touching your
wallet as you contemplate the purchase of a new batch of brass.
The reason for the case neck splitting is that the
necks have become to hard and are not able to take the expansion and contraction
accompanying the rapid pressure excursion which occurs within the case when it
The thinning of the case necks occurs when the
cases are repeatedly resized. Each time the case is run into the sizing die, it
is squeezed back to it's original dimensions. That is, the brass is moved from
one dimension to a smaller one. You have heard the old adage, "you can't put two
pounds of stuff (original word omitted), into a one pound bag". The same holds
true here, also. When the case is squeezed, the "extra" brass has to go
somewhere. The somewhere that it goes to, is "out the front". The case gets
longer. The "extra" brass comes from the body and shoulder of the case --
eventually, the case will "run out of the extra bras". As the case gets too
long, it will have to be trimmed. When the necks get too thin, the cases will
have to scrapped.
Another thing that happens during the resizing also
contributes to the hardening of case necks. As the brass is squeezed back to
it's original dimensions, it is work hardened even more. Each trip through the
chamber and the resizing die contributes to the work hardening of the case
necks. The usual method of correcting this condition is to anneal the
Factors Affecting the Annealing
You might assume that brass is brass and that a
little heat can't possibly hurt anything. After all, the heat in the chamber is
actually hot enough to melt steel, isn't it? Yes, it is. But, the "fire" and
attendant heat are of such short duration that the brass (including the chamber
and barrel) are virtually unaffected. In order to change the grain structure,
time (as well as temperature) is an important component. After too much heat
and-or too much time, the brass will be over annealed. It will be too soft, and the
entire case will be affected.
The trick is to heat the neck just to the point
where the grain structure becomes sufficiently large enough to give the case a
springy property, leaving the body changed but little, and the head of the case
Brass is an excellent conductor of heat. A flame
applied at any point on a case for a short time will cause the rest of the case
to heat very quickly. There are several temperatures at which brass is affected.
Also, the time the brass remains at a given temperature will have an effect.
Brass which has been "work hardened" (sometimes referred to as "cold worked") is
unaffected by temperatures up to 482 degrees (F) regardless of the time it is left
at this temperature. Remember, water boils at 212 degrees (F), and oil heated in a
frying pan easily reaches 500(F) or more degrees. (All temperatures will be
At about 495 degrees (F) some changes in grain
structure begins to occur, although the brass remains about as hard as before --
it would take a laboratory analysis to see the changes that take place at this
If cases are heated to about 600 degrees (F) for one
hour, they will be thoroughly annealed -- head and body included. That is, they
will be ruined. (For a temperature comparison, pure lead melts at 621.3 degrees
The critical time and temperature at which the
grain structure reforms into something suitable for case necks is 662 degrees
for some 15 minutes. A higher temperature, say from 750 to 800 degrees, will do
the same job in a few seconds. If brass is allowed to reach temperatures higher
than this (regardless of the time), it will be made irretrievably and
irrevocably too soft. Brass will begin to glow a faint orange at about 950
degrees (F). Even if the heating is stopped at a couple of hundred degrees below
this temperature, the damage has been done -- it will be too soft. From this
discussion we can see that there are four considerations concerning
1> Due to conduction, the amount of
heat necessary to sufficiently anneal the case neck is great enough to
ruin the rest of the case.
2> If the case necks are exposed
to heat for a sufficient period of time, a lower temperature can be
3> The longer the case necks are
exposed to heat, the greater the possibility that too much heat will
be conducted into the body and head, thereby ruining the cases.
4> The higher the temperature,
the less time the case necks will be exposed to heat, and there will
be insufficient time for heat to be conducted into the body and
You can see that there are a couple of catch-22's involved in this
annealing business. On the one hand, the brass conducts heat quite
rapidly, and a fairly high temperature with sufficient time must be
attained to do the job. On the other hand, too much time cancels the
effect, and we will be left with a case that is too soft and not suitable
for anything but scrap. Obviously, there must be a solution; otherwise,
not even the cartridge manufacturers could get the job done.
In order to solve the
problems of automatic case annealing, we will need to accomplish the
1> Control the time the case
neck will be heated.
Control the amount of heat delivered to the case neck.
Cause the case to turn at a constant rate
while it is being heated so that the heat is applied evenly around
4> Prevent, or
sufficiently limit, the conduction of heat into the case head
Add to the above list the additional
frills listed below, and you'll be in hog heaven:
annealer must be easy to set up.
The annealer must be simple and easy to maintain.
The process must be "dry" -- that is, the brass should not become
wet and have to be dried before reloading.
The annealing process must be easy... it must not require expensive
testing equipment or unusual skills and knowledge.
The annealing process must be fairly quick. The machine operator
should be able to anneal several hundred cases per hour.
The process must be repeatable and predictable. Cases must be
uniform from case to case, as well as from session to session.
Annealing and Under Annealing
When cartridge brass is under annealed, virtually
nothing has changed. If your case necks have become work hardened, they will
still be work hardened, You will not see any improvement in case life or in
accuracy. You will assume (incorrectly) that annealing is a waste of time and in
this case, it is.
Over annealing is certainly the worst condition,
and can even be dangerous, as pointed out above. Over annealing has two aspects:
over annealing of the case neck only, and any
annealing of the
lower half of the case. There is no particular danger to over annealing the case
necks, which is the usual result of standing the brass in water and heating the
necks with a torch. All that will happen is that your accuracy will not improve,
or it may become worse, and the cases may seem to be a little more sticky during
extraction. Case life will be improved because the necks are soft -- too soft.
However, you will conclude that annealing is not what it is cracked-up to be,
and may even be a waste of time.
Any annealing whatsoever of the cartridge base is
over annealing and is dangerous.
This area of the brass must retain the
properties it had when it left the factory. If it is made the least bit softer,
let alone "dead" soft, the stage is set for another shooter's nightmare. At the
very least, you may get a whiff of hot gas directed toward your face. At the
worst, you can be seriously injured as your gun behaves more like a hand grenade
than a firearm.
I once heard a tale of a gentleman who placed his
brass on a cookie tray and placed the whole batch in an oven at 650 degrees for
over an hour. He wasn't hurt -- at least seriously. His attitude toward
annealing is very negative.
Cartridge brass which has been annealed
over it's entire length will exhibit signs of excessive pressure even with
moderate and reduced loads. Indeed, cases in this condition are subjected to
excessive pressures. Any pressure is excessive. Head separation, incipient head
separation , stuck or sticky cases, blown primers, swollen cases, swollen case
heads, enlarged primer pockets) I mean R-E-A-L-L-Y enlarged) and just about
every other sign of excessive pressure imaginable can occur with cases which
have been annealed over their entire length.
Testing Cartridge Brass for Hardness
not a definitive test
of case hardness; it is more of an illustration than anything else. It requires
a pair of small Vice-Grips and a few bottle neck rifle cases in
various conditions of use: a factory fresh empty case, two cases that have not
split but have been fired many times, and a couple of extra cases to set the
jaws of the Vice Grips.
Place one of the used cases base down in a shallow
tray containing water up to the lower 1/3rd of the case, and
deliberately over-heat the case neck -- bring it to a red heat.
Adjust the Vice-Grips until the jaws barely touch
the case neck when they are fully closed. Then, Carefully adjust them to go a
few thousands of an inch beyond that point. The jaws should close until you can
just barely visibly detect that the case mouth is deformed when the Vice-Grips
Ordinary pliers are not good for this demonstration
because it is too easy to go too far. Vice-Grips, on the other hand, have an
adjustable limit to which they can be closed.
Squeeze the neck of the used, but un-annealed case.
Note the pressure required. Also note that when the pressure is released, the
case neck springs back to it's original shape.
Squeeze the neck of the factory fresh case. Once
again note that the case neck springs back to it's original shape, and that it
takes slightly less pressure to deform it than the un-annealed case.
Now, squeeze the annealed case. The pressure to
deform it is markedly less and when it is released, the case mouth remains
deformed -- no spring.
One more test -- stand the annealed case on a metal
plate (no water over the base) and heat the upper half to a red heat. Hold the
heat for a few seconds and then let it cool. Adjust the Vice-Grips so that they
can put considerable squeeze on the head area and crush the annealed case. Now
crush one of the normal used cases. The difference is dramatic. Don't test an
over annealed case in a gun just to see what happens -- take my word for it, the
results can be dangerous to life, limb and eye, not to mention the condition of
the gun. Now crush all of the test cases so that they won't get mixed in with
some good stuff.
If you are a chemist or a metallurgist and know how
to do it, you can make some photomicrographs of sections taken from the various
critical points of several cases for reference. Of coarse, you could have been
out on the range having a good time instead of fussing with such things, but to
each his own.
Selecting the Proper Torches
Almost everyone has a propane torch. They are
pretty handy gadgets to have around the house. You will need two of these
torches for the BC-1000 Cartridge Case Annealer. Before you go out and buy
another torch or two, we need to have a brief discussion on torches. There are
torches, and then there are torches.
Some of the older type torches have large burner
tips and very crude fuel control systems. Most of the newer torches have very
efficient tips and fuel valves that are quite precise. The newer torch tips are
small in diameter -- about 1/2
inch -- while most of the older models are in the
5/8ths inch range. There is nothing wrong with the older style
torches, and you will find that they can perform quite well. However, if your
torch's flame is hard to control, the tip "spits" or "flares", or the tip has
become too deformed because of being dropped a few times too often and no longer
delivers an even flame, some new torches may be in order.
I happen to favor the BernzOmatic Model JTH-7
torch. The tip is efficient, and the valve is not too sensitive. Any equivalent
torch will do nicely as long as the tip will fit through the torch holder. This
torch will deliver about 4200 BTU.
Preparing The Brass for Annealing
The brass does not require any special preparation
before it can be annealed. However, you will need a few polished cases in order
to determine the correct temperature. This is important if you want first class
results. If your first batch of brass will be pistol brass, don't use plated
cases for the testing. Plated cases anneal just fine, but you will not be able
to see the color of the brass as it heats up under that shiny coating of nickel.
If you have a polisher, polish the brass before
annealing it. If you do not have a polisher, use a little Brasso or other brass
polish on a dozen or so cases Polish them about half way down the case by
putting a little Brasso on a soft cloth and turning them by hand. If you have a
polisher, I don't need to tell you how to polish the brass.
One more thing
- I know this goes without saying, but I'll say it any way:
Make Sure There Are
OR Charged Cases in the Annealer !!
Place one of the polished cartridge cases in a hole
near the flame and let it go around the wheel and drop out. This will take a few
seconds so be patient. If you are using a rimmed, semi-rimmed or belted case, it
will have to be fed from the bottom of the shell wheel and held until the base
can be dropped on the feed ramp. Rimless and rebated cases can be fed from the
It should be noted that one of the purposes of the
shell wheel is to preheat the case as well as provide a heat sink to keep them
from being over heated. All cases should be fed into the shell wheel in the area
of the feed ramp. Starting the cases too close to the flame will not give them
time to preheat to 212 degrees (F).
On a bottle neck rifle case, the central portion of
the flame should be on the case neck, and the outer portions of the flame will
"wash" over the shoulder and down the side of the case for a short distance. As
the cartridge goes around the wheel, it will turn, causing the entire periphery
of the neck to be exposed to the direct flame at one time or another.
With this setup, the neck will actually reach a
temperature between 750 and 800 degrees. Remember, it is time and
temperature that does the job. We have raised the temperature
sufficiently to be able to anneal the case necks in 6 to 8 seconds.
The shoulder will be a bit cooler than the neck,
and the body cooler yet. The case head will be below 300 degrees (F), which is
well below the critical temperature of 482 degrees (F) at which the first changes in
grain structure can occur.
As the case progresses through the flame, watch it
closely. You will detect a slight -- barely perceptible -- change in color. As
the exits the flame,
there should be a light bluish
color which develops at the shoulder or a little below it, while the shine
remains on the case body. The loss of the shine is a clue that
the case got a little too hot. On bottle necked cases you will see that the neck
turns to a noticeably deeper "gold" color.
If the shine is gone, the flame can be adjusted or
the angles of one or both torches can be changed so the case is not in the flame
as long. The height of one of the torches may be changes so that the cases are
not in the hottest part of the flame. The color will usually develop as the case
is in the last flame.
If the cases do not develop any color at all, then
increase the intensity of the flame or adjust the flames so that they play more
directly on the case necks, or a combination of the two.
In any case, you are very much more likely to over
anneal than to under anneal.
Do not expect that the color will be as dark as it
appears on military cases. This darkness of the color on military cases occurs
over a period of time, as do the delicate reds and purples around the dark
color. If you leave one of your cases sitting out for a few months, it will
begin to take on the same appearance that military cases have.
If the cases have lost their shine, they were close to a
red heat and and may or may not be too soft. You can gauge the softness to some
degree by using the Vice-Grip "test" described above. If the case mouth doesn't
spring back after being slightly deformed, the case is trash. Don't waste your
time with it.
When you get the faint blue color and the shine
remains on the case, you have everything adjusted to perfection. Start stuffing
those little brass cases in those little round holes until your done. Make
mental note of your set-up, and you'll be able to repeat it in about three
minutes the next time you are ready to anneal.
When To Anneal
Ok, now that you know how to anneal, you need to
know when to anneal. If you shoot light loads, you can go a long time between
annealing. Moderate loads will necessitate annealing a little more often.
Normal loads will work harden the case after an amazingly short time. Hot or
maximum loads will require annealing very often -- something on the order of
once after every two to four firings.
You must also consider that some work hardening
occurs when the brass is resized, so the number of firings do not tell the whole
story. Another consideration is the chamber size of your gun. If you have a
"loose" chamber, you will expand your brass more. It will need to be squeezed
more when it is resized, thereby causing it to be worked a little more than
Another indicator is the opening up of your groups.
When you start getting fliers and abnormally large groups, check your case necks
along with all of the other variables; it may be time to anneal. If your a
chemist or metallurgist, you could acid-etch a case neck and microscopically
inspect the grain size.
In the end, it will be your own experience that
will determine the frequency of annealing -- just like every other aspect of
handloading, there are many variables which are peculiar to your particular
problems, methods, techniques, loads, components and guns. You are the final
The next question is, should cases be annealed
before reforming? I will let Mr. Earl Naramore answer that Question ("Principles
& Practices of Reloading", Small Arms Technical Publishing Company, 1954):
As to whether cases should be annealed
prior to re-forming them to some wildcat shape, much depends upon circumstances.
Re-forming such cases in an ordinary resizing die puts a crushing force on them
and I fear that if this cock-eyed method is used, the annealing would only make
the crushing of the cases easier. But if a preliminary break-down die is used,
there would probably be an advantage to annealing before the re-forming is done;
it depends on the force of the break-down die, the nature of the case, and such.
If cases are annealed for re-forming, the angle of
the flame should be set back and it should be carried to a point where the shine
on the cases disappears. Following the annealing, the cases should be polished
again outside before any sizing is done on them. The loss of shine means that
the surface is oxidizing and such a surface will give excessive resistance in a
die. It is doubtful if one would have enough of these special cases to justify
mechanical washing or polishing and a little rubbing up with Bon-Ami on a wet
cloth will do. It will be recalled that washing and water polishing follow every
anneal during manufacture of cartridge cases. [Mr.
Narmore devoted quite a bit of space to this subject in his classic book].
If you are forming brass and have definite
instructions as to when, where and how much to anneal, by all means, follow the
instructions that you have been given. The "instructions" above are more in the
form of "guidelines" rather than definite instructions.
The last question is, "Do I anneal before resizing,
or after"? Theoretically annealing does not change the diameter of the case
neck. In practice, it may or may not, depending on how much the metal is
stressed. Therefore, you should always anneal before resizing.