The primary reason for annealing rifle brass is preventing case-necks from cracking—and they will, eventually, because firing and resizing cases “work hardens” brass, making the thin necks brittle. Most rifle cases will survive 4-5 firings, and some will last longer, depending on the brand and method of resizing. However, many handloaders avoid the issue entirely by retiring brass after several firings.
I did this for many years, selling well-fired cases for scrap at a local recycling center, using the money as partial payment for new brass. This worked fine back when bulk brass was widely available and relatively inexpensive, but that started changing when demand for ammunition and components rose enormously during the Obama administration.
Some companies selling bulk brass also happened to be major ammunition manufacturers. When demand for ammunition rose, they found it more sensible (and profitable) to use new cases to make ammo. As a result, it wasn’t always possible to buy a batch of new brass, so many handloaders decided to make their old brass last longer.
This coincided with an ongoing trend toward handloading for finer accuracy, whether because more shooters started competing in target games, shot at longer ranges, or decided half-inch groups were necessary for slaying white-tailed deer, after our hunting buddies bragged about their tiny groups. Many handloaders discovered that paying a premium for more consistent brass, or “uniforming” common brass, resulted in finer accuracy. They didn’t want to toss expensive or reworked cases after a few firings, so started annealing brass.
I started annealing brass before the Obama shortages, primarily due to fooling with wildcat cartridges. Forming wildcat cases required both time and, often, the expense of fire-forming, but I was somewhat startled to find that annealing wasn’t very complicated or time-consuming.
My surprise was due to the standard misinformation published for many years, which went something like this: “Stand your fired cases in a metal pan, then pour enough cold water into the pan to cover everything but the shoulders and necks. Heat the brass with a torch until it glows red, then knock the cases over into the water, quenching the hot brass to finish the annealing process.”
It may date me some to admit this, but that was the standard advice back when I started handloading, regurgitated countless times in shooting magazines and loading manuals. While some handloaders still anneal cases that way, there are several problems with the technique, including being unnecessarily complicated.
Cartridge brass averages around 70% copper and 30% zinc (though that can vary somewhat), and often contains tiny amounts of other elements. This alloy is
strong enough to contain pressures of over 60,000 pounds per square inch, flexible enough to seal the rear of the chamber, and to hold bullets firmly yet release them smoothly.
The final hardness of a new case also depends on the work-hardening caused during forming at the factory. Work-hardening is essential to the thick head of a rifle case, the portion that contains pressure, but makes the thin neck brittle, the reason cartridge manufacturers anneal necks after the final forming.
However, no manufacturer I’m acquainted with heats the necks until they glow red, because any hint of red means the temperature’s around 800 degrees Fahrenheit. Zinc melts at 787 degrees, more than 1000 degrees below the melting point of copper. Over-heating brass can actually melt out some zinc, turning the brass permanently soft.
That’s the primary problem with the old annealing technique, but unlike most other metals, annealed brass doesn’t require quenching to remain soft. If you want to reload the dunked cases anytime soon, their insides have to be dried, but they cool pretty quickly if simply left standing in water. (Of course, if you decapped the cases before standing them in water, they’re going to be wet inside anyway.)
The real purpose of placing cases in water is to avoid annealing the case-heads, since they need to remain hard. A few handloaders have annealed entire cases, whereupon they discover (if they survive) they can come apart when a cartridge goes bang.
But annealing really doesn’t require standing cases in water, and torching a pan full of brass tends to heat necks unevenly, no matter how nimbly a handloader moves the torch around. Annealing enhances accuracy by allowing bullets to leave necks more consistently, but a neck softer on one side tends to tilt bullets slightly as they start down the bore.
Annealing brass also doesn’t involve heating to a single, precise temperature. In a way it’s like cooking pork: Many people “know” pork needs to be heated to 160 degrees Fahrenheit to kill trichinella larvae—but 160 degrees is merely the temperature that kills the larvae within seconds. Cooking pork to somewhat lower temperatures for longer periods also whacks ‘em.
Similarly, brass anneals at temperatures as low as 480 degrees, but the process takes much longer. Even annealing at 600 degrees requires an hour, far too long for our purposes. Instead, we want to quickly heat necks to just under the melting temperature of zinc, avoiding the problem of heating the rest of the case, especially the head.
Luckily, this isn’t difficult, since heat-testing paints are easily available, and a small bottle lasts a long time. There are several brands, but the one I’ve used most is Tempilaq’s 750-degree paint. Dab a little inside the case-mouth, heat the neck just until the color disappears, and the neck’s annealed.
Most handloaders, however, don’t paint the inside of every neck. Instead they paint maybe five cases, then count how long the color takes to disappear after applying the heat source. After that, they heat unpainted necks for the same count.
The simplest and least expensive annealing method I’ve ever encountered was devised by Fred Barker, who published his results in the now-defunct magazine Precision Shooting. Fred sent me a copy of the article years ago, and I’ve used his technique with fine results ever since, including it in the first chapter of The Big Book of Gun Gack, “Working Up a Load in the 21st Century.”
If you don’t have a copy, here’s a rerun: Fred knew that a candle’s flame is far hotter than the annealing point of brass, so applied heat-paint to the necks of various cartridge cases and started experimenting. He found that holding a case in his fingertips about halfway up the body, then placing the neck in the tip of a candle’s flame and turning it back and forth until the case grew too hot to hold, heated the brass to just about the right temperature. When his finger-tips got hot, he’d drop the case on a wet towel, then use the towel to wipe the candle-soot from the outside. Presto, annealed case!
I’ve found candle-annealing usually takes about 10 seconds on cases about the size of the .308 Winchester or .30-06 Springfield, and slightly longer on full-sized magnums. Add another five seconds to wipe off the case and the annealing rate is about four cases a minute, so twenty cases can be done in five minutes. Since the “set-up time” of lighting a candle and wetting a paper towel is minimal, this is how I anneal most of my big game rounds.
It works a little faster on smaller cases, taking about 6-7 seconds on .22 Hornets. With care you can also use a propane torch, which doesn’t produce soot so bypasses the need to wipe off the cases—but I’m still not going to finger-anneal 500 Hornet cases. Which is exactly why I have several thousand new Hornet cases on hand.
Some handloaders put a steel socket in a drill motor, then place a case base-first into the socket to turn the neck over a flame. This works too, and in fact for a while Hornady sold a kit for drill-annealing—now apparently discontinued—with three sockets for varying case-sizes. (It also included a bottle of 475-degree Tempilaq, applied below the case shoulder to make sure the annealing didn’t reach the head.) This works partly because a metal socket functions as a “heat sink,” keeping the head of the case cooler. I used a Hornady tool for a while and it worked fine, but it wasn’t any faster than the finger method.
Those are the two easiest and cheapest methods of annealing. You can buy faster machinery and spend well over $1,000, but for most of us, these two methods are the most practical.
Want to know more about the thousand-dollar options? Ah, yes, we are a rifle loony. Check out Gun Gack II: More Stuff about Handloading & Hunting Rifles.