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TO ANNEAL OR NOT TO ANNEAL?
So, you’ve been reloading for a while and have a good supply of brass. Now, after 5 to 7 firings, you’re seeing brass necks cracking. Premium quality rifle brass is expensive. 338 Lapua is about $3.00 ea.,.308 Win. $1.00 ea.
You want to extend your brass life and have heard of cartridge case neck annealing. A knowledgeable reloader may have advised that he anneals case necks, which extends brass life and improves accuracy. This fellow may have cautioned regarding the hazard of annealing the case head, as this may cause a rupture to blow out when fired. This can wreck the firearm, possibly injuring the shooter. After hearing this, you may have put the idea of annealing case necks out of your mind for a while. As time has progressed, you may have scrapped your original supply of cases and are again experiencing case failure from cracked necks. When a case is fired and reloaded, the neck is moved 3 or 4 times. This results in work hardening. The only cure is neck annealing. The
bench rest shooter who anneals his brass after every firing set an outstanding 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, as well as superb accuracy. By now you may have decided it would be good to at least investigate the case of neck annealing.
Many years ago, this reloader attempted annealing some brass with unacceptable results. At that time, information was almost nil. The instructions were to stand the cases up in a pan, add water to 1/3 the depth of the case. This way, the head could not be heated above 212° F. At 482o F, brass begins to anneal. 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 of the case neck needed or what might happen if it was overheated. With this information, annealing was tried with cases standing in a shallow bath of water. A propane torch flame was applied to the case necks. There was no method to measure neck temperature and a number of the.30-06 cases were overheated. After all, if a low red glow is good, then a bright red color had to be better. This seemed like good logic to me, right? no wrong. By the way, at what temperature is brass at a low red glow anyway? Years later, it was determined that a low red glow, even in dim lighting, is too hot. All of the cases on hand were annealed in the above manner to a very good red glow. The next reloading, these cases were neck sized and many failed with collapsed shoulders. The neck and the top of the shoulders were too soft. Nothing was gained in conservation just by producing scrap brass. At this time, cartridge case neck annealing was abandoned.
Years later, the sport of high-powered offhand rifle silhouette shooting was of interest and a quantity of 7.62 X 51 brass was needed. A good supply of once fired military brass was obtained. Some was match brass fired in rifles, others from machine guns, which have generous chamber dimensions. It was determined the entire lot of about 1,000 pieces should have the necks annealed.
Research began 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. The water bath only assures case head annealing cannot occur. Metallurgists advise water quenching has no significant effect when annealing cartridge brass necks. Cartridge brass is 70% copper and 30% zinc, with an annealing temperature of 482o F. A cartridge case brass manufacturer stated that 700 o F. was the low temperature and 800 o F. was the high temperature for properly annealing cartridge case necks. Once quickly brought to that temperature, then air-cooled proper case neck annealing is achieved.
With this information, the target neck temperature was set at 750o F. Also, the case head had to be kept under 482o to avoid annealing it. These were now the parameters to successfully anneal the case necks.
An infra-red heat measuring gun was investigated to determine temperature. The manufacturers advised that to obtain accurate readings, all brass had to have the same reflective finish with the infra-red gun calibrated to that finish. This would be doable as most serious reloaders clean their brass anyway, only requiring inspection 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, so the heat gun was abandoned. Brass neck annealing occurs rapidly; the necks would be in the annealing flames for only a couple of seconds. Temperature readings had to be instant and accurate. 750 Degree Tempilaq® solved this problem.
There are a few cartridge brass annealing machines on the market, costing from about $400.00 to over $1,400.00. A cartridge brass annealer only performs one step in reloading. It did not seem cost effective to invest that much in a tool performing one operation.
A new design was sought; it would have to be efficient, practical, and affordable. An invention was in order; a design requirement was a rig that easily positioned a case neck in 2 opposing flames for quick annealing and allowed quick removal when annealing occurred. A prototype was built using a 1″ square aluminum block 4″ long having a hole bored in each end larger than the outside diameter of the cartridge case head. This design allows a case to slide in and out easily. A hole was cross-drilled in the center of the 4″ aluminum bar for an axle. This aluminum bar is now the cartridge case holder. A wooden knob was installed to turn the cartridge case holder by hand as it gets hot, acting as a heat sink on the case. In use, a case is inserted clear of the flame, then rotated into and between two opposed propane torch flames, impinging on and wrapping around the case neck, heating it uniformly. The prototype worked perfectly; production models are now available as the Anneal-Rite. A variety of cartridge case holders are available which accommodate hundreds of different cases from.40 S&W pistols to the largest ones taking.50 BMG and even.600 NE. The entire unit, with one common-size cartridge case holder, sells for around a hundred dollars, including one bottle of 750 Tempilaq® heat indicating fluid, which is guaranteed accurate to +-7.5o. Annealed cases are processed at 500 to 600 per hour. The Anneal-Rite comes with a money-back guarantee, assuring perfectly annealed case necks. A demo video can be viewed at www.cartridgeanneal.com. Customer service is available; call 479-629-5566. You will get a person on the line from 9am to 9pm Monday through Saturday. You do not have to suffer with premature case failure or spend four hundred to fourteen hundred dollars. This reloader got a 5 shot.620″ group at 300 yards using the neck annealed 7.62 X 51 military cases mentioned.
Tom Wilson ©