Many precision shooters; benchrest, target, varmint & long-range hunters strive to make the most accurate reloaded ammunition possible. Proper brass cartridge case neck annealing provides consistent bullet to neck tension increasing accuracy and extends brass life. Correct annealing rejuvenates the cases neck to the ductility close to that when manufactured.
Please note, PROPER and CORRECT, are the key requirements here! Worst case reported to date, one reloader over annealed his brass, got it nice and red, when he fired it the neck of a case adhered to the inside of the chamber. This gentleman had to pound on a rod inserted down the bore. He was finally able to drive the case out however some of the neck tore off as it had bonded to the inside of the chamber. He stated It took a lot of work to finally remove the brass fused in his chamber.
This is a very rare case, obviously to be avoided, properly annealed brass case necks will never suffer this failure, but the job needs to be done correctly.
What is Brass Cartridge Case Neck Annealing?
In a nutshell a heating process altering the brass microstructure by rapidly raising the neck temperature to 750°F. then allowing it to air cool.
The goal of annealing is to achieve optimum ductility by relieving internal stresses built up by firing and reloading cycles which work hardens the neck.
Properly done, which is easy using the Anneal-Rite machine as it guarantees perfect results, returning the brass neck very close to new factory condition.
Why Anneal Brass?
Two definite benefits. Annealing your brass case neck increases brass life returning the ductility in the neck area, negating work hardening induced from repeated firing reloading cycles. Second benefit, it increases accuracy providing consistent case neck to bullet tension.
Annealing case necks has proven to be one of the steps in precision reloading for accuracy. Stress buildup will make metal fail from work hardening.
Test this, take a steel paper clip, repeatedly bent & straightened in the same place, it will break. Brass cartridge cases react the same, without annealing the case neck will work harden and crack, this usually starts around 5 to 7 firing reloading cycles.
In most rifle chambers when a case is fired the neck expands about .010” & springs back a little allowing extraction. When reloaded the neck is resized smaller by as much as .012”. Some reloading dies now expand the neck some from the inside. Next the bullet is seated expanding the neck .001” to .002”. This firing reloading cycle work hardens the brass case neck.
Annealing case necks is particularly helpful when forming wildcat cases, re-configuring the shoulder, enlarging or reducing the neck size. Annealing the neck and possibly a little of the shoulder ensures the brass properly forms to the chamber when fireformed.
To anneal your cases properly, heat the necks to 750°. F. then allow the case to air cool, no need to quench in water. Water quenching is a throwback to a very old method and is not needed. Information gleaned from brass manufacturers reveals they air cool the brass after annealing. If annealed brass turns a bright, glowing red it’s over annealed and becomes too soft.
One cartridge case manufacturer stated 700°F. to 800°F the proper temperature range they anneal the case neck. This is the reason the Anneal-Rite case annealing machine is furnished with 750°F.
Tempilaq as it indicates accurately to a guaranteed accurate to + – 7 ½ °F which is the exact center of the recommended heat range.
What is Brass Work Hardening?
This is the process of increasing the strength and hardness of a metal by subjecting it to plastic deformation. In manufacturing new cartridge cases the brass is blanked, drawn, bent or worked resulting in work hardening which is a must in the case head (base) area.
Work hardening is used to make the base harder & stronger. The base of cartridge cases does not expand unless an over pressure load is fired, which must be avoided. The base is deliberately work hardened in manufacturing and must remain in this state.
Manufacturers take great care in laboratory examination of grain structure in various places on cartridge brass to determine it is correct for that area.
So properly anneal your case neck, and leave the base as originally made.
What Makes Modern Annealing Different from Old Processes?
There have been many advances in the field of annealing, today there are much more consistent methods than the old-fashioned way. More than 60 years ago the recommended method was to stand the cases up in a pan, add water about 1/4 the case height. Next heat the neck to a low red glow with a torch, then tip it over in the water.
Why tip them over, no one knew, metallurgists state this does nothing in the annealing process. Standing cases up in water did guarantee the case head could not be annealed however the same thing occurs with air cooling.
See the Anneal-Rite demonstration video at www.cartridgeanneal.com, this proves the case head is not annealed as it is held in an aluminum holder acting as a heat sink. This is a foolproof method as the Anneal-Rite is supplied with 750° F.
Tempilaq which is the proper annealing temperature. This unit is guaranteed to provide perfect results on every brass case neck annealed.
The Bottom Line: Unraveling the Art and Science of Brass Annealing for Reloaders
As a reloader, it is crucial to understand the science and art of brass annealing to get the most out of your brass. By properly annealing your brass, you can extend its lifespan and improve accuracy.
There are a few things to keep in mind when annealing brass: first, the neck needs to be heated evenly in order for the annealing process to work correctly. Second, you must be careful not to overheat the brass as previously stated.
Looking for an Annealing Brass Case Machine?
At Enterprise Services, LLC, we offer an affordable machine with guaranteed perfect results. This comes with easy step-by-step instructions always producing perfectly annealed cases at exactly 750° F. See the demonstration video at www.cartridgeanneal.com If you have questions call (479) 629-5566 Mon.-Sat. 9am to 9pm.