TO ANNEAL OR NOT TO ANNEAL?
So, you have been reloading for a while. You accumulated a supply of brass for your favorite firearms. Now after 5 to 7 reloadings you find you are losing brass with necks cracking. Premium quality rifle brass is rather expensive, .338 Lapua will dig into your wallet at the rate of 3.00 ea., less exotic hulls like .308 Win. $.90 ea. for high quality cases.
You are contemplating prolonging the life of your coveted brass as you have heard of cartridge case neck annealing. Some knowledgeable shooter at the range advised he does this and stated the benefits are, increased accuracy and greatly extended case life. This experienced gentleman may have also advised if you accidentally anneal the case head you have created a very dangerous situation. If the case head is annealed it can blow out when fired, wreck the firearm with possibly injury to the shooter. After hearing this you may have put the idea of annealing case necks out of your mind for a while. As time progressed you may have scrapped your original supply of cartridge cases and are now again experiencing case failure. When a case is fired and then reloaded the neck is moved 3 or 4 times, this results in work hardening and the only cure is neck annealing.
A bench rest shooter who anneals his brass after every firing set an impressive record with a group less than 1” at 600 yards, the 6 BR brass he used for this record was fired for the 58th time. This represents a dramatic extension of brass life. By now you may have decided it would be prudent to at least investigate case neck annealing.
Many years ago, an attempt at annealing was tried by the author with unacceptable results. At that time cartridge case neck annealing information was very limited. The instructions were to stand the cases up in a pan, add water to a depth 1/3 up the side of the cases. With the cases setting in water the case heads could not be heated above 212 degrees F. the boiling point of water, and brass begins to anneal at 482 Deg. F. The instructions said to heat each case neck with a torch to a low red glow evenly all of the way around and then tip it over into the water. No mention was made as to the proper temperature the case neck needed or what might happen if overheated. With the scant information available annealing was begun with the cases in a pan standing up in water. A small propane torch flame was applied to the case necks. There was no way to measure neck temperature and a number of the .30-06 cases were over heated. After all, if a low red glow is good then a bright red color had to be better, this seemed like just pure and simple good logic, right ~ no wrong. And by the way what temperature is brass at a low red glow anyway? Years later it was determined a low red glow, even in dim lighting is too hot. All of the cases on hand were annealed in the manner described to a very good red glow. At the next reloading quiet, a few cases were lost due to the shoulders collapsing even though they were just neck sized. The necks and the top of the shoulders were too soft. Nothing was gained in conservation, just more scrapped brass. At this time cartridge case neck annealing was abandoned.
Years later the sport of high-powered rifle silhouette shooting became of interest. This presented a need for a good quantity of 7.62 X 51 brass. A large supply of once fired military brass was obtained. A good portion was match brass fired in match rifles. Mixed in was a larger quantity of brass fired in machine guns, which have generous chamber dimensions. For this reason, it was determined the entire lot, around 1,000 pieces of brass, should have the necks annealed prior to being put into service.
It was now time for research hoping this time to obtain precise cartridge brass neck annealing information. It was soon found that cartridge case necks do not have to be quenched in water after they are heated for proper annealing, the water bath treatment only assures case head annealing will not happen. Metallurgists advised water quenching has no significant effect when annealing cartridge brass necks. Cartridge brass is 70 percent copper and 30 percent zinc. It begins to anneal at precisely 482 degrees F. Research revealed 700 was the low and 800 degrees F. the high to successfully anneal cartridge case necks. Once quickly brought to that temperature then air-cooled proper case neck annealing is achieved. The goal was to devise a method to bring the case necks to the center of the proper temperature range, 750 degrees became the target temperature. At the same time heating the case head to less than 450 degrees would retain the proper brass temper in this area, which is important. This became the parameters to successfully anneal the case necks.
An infra-red heat measuring gun to get accurate readings was researched. The manufactures advised to obtain accurate readings all brass had to have the same reflective finish. Next the infra-red gun would have to be calibrated to that finish. This would be doable as most serious reloaders clean their brass anyway, this would require inspecting all brass in the batch being worked for a uniform finish. The manufacturer of the infra-red heat gun then stated it would not read the brass temperature correctly if the beam was directed through a flame. For this reason, the heat gun was ruled out. It was determined neck annealing occurs rapidly, the case necks would be in the annealing flames for only a couple of seconds.
There are a few carousel style cartridge brass annealing machines as well as other designs on the market. The prices for these machines run from about $400.00 to $500.00. As this type of device performs only one step in preparing brass for reloading, it did not seem cost effective to invest that much for a machine accomplishing just one operation.
A new design was sought; it would have to be efficient, practical and affordable. A design that would get the case neck into the flame and out quickly as soon as annealing occurred. The design that evolved utilizes rotation in a vertical plane rotating on a horizontal axle. A prototype was built using a 1" square aluminum block 4" long with a hole about an inch deep and larger than the outside diameter of the cartridge case drilled in either end. This design allows the base of a cartridge case to easily slide in and fall out. A hole was cross-drilled in the center of the 4" aluminum bar to accept an axle. This aluminum bar is now referred to as the Cartridge Case Holder. A wooden knob was installed to turn the Cartridge Case Holder by hand as the aluminum bar gets hot as it acts as a heat sink on the case. In use, a case is inserted with it clear of the flame, then rotated into and between two opposed propane torch flames impinging on the case neck. The flames rap around the neck heating it uniformly. The prototype worked perfectly. Production models were produced with propane cylinder holders. This unit is now being marketed as the Anneal-Rite Machine. Ten standard Cartridge Case Holders are available which accommodate many hundreds of different cases from .40 S&W pistol with the largest one taking .50 BMG and even .600 NE. The entire unit with one common size cartridge case holder sells for less than a hundred dollars including one bottle of 750 Tempilaq®. In time studies 500 to 600 cases per hour can be annealed. The Anneal-Rite comes with a money back guarantee assuring perfectly annealed cartridge cases. A demo video can be viewed at www.cartridgeanneal.com or by calling Anneal-Rite at (479) 629-5566. You do not have to suffer with premature case failure, or spend Four Hundred Dollars or more. Increased case life and accuracy will be the benefits. A 5 shot 5/8" group was recently achieved at 300 yards using the neck annealed 7.62 X 51 cases earlier in the article.
Tom Wilson ©