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Campfire 'Bwana
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Campfire 'Bwana
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If you put Taco Bell sauce in your ramen noodles it tastes just like poverty
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The Scientific Method is based on making intentional wrong assumptions and testing them, and learning from mistakes.
Changing theories as needed to accommodate the results.
That IS the scientific method...based on observation of the results.
"Supernatural divinities are the primitive's answer to why the sun goes down at night..."
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Joined: Jan 2010
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Campfire 'Bwana
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Campfire 'Bwana
Joined: Jan 2010
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The Scientific Method is based on making intentional wrong assumptions and testing them, and learning from mistakes.
Changing theories as needed to accommodate the results.
That IS the scientific method...based on observation of the results. No shît?
If you put Taco Bell sauce in your ramen noodles it tastes just like poverty
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Joined: Jan 2010
Posts: 32,130 Likes: 1
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jan 2010
Posts: 32,130 Likes: 1 |
The Scientific Method is based on making intentional wrong assumptions and testing them, and learning from mistakes.
Changing theories as needed to accommodate the results.
That IS the scientific method...based on observation of the results. You need to reread your Karl Popper and Thomas Kuhn.
If you put Taco Bell sauce in your ramen noodles it tastes just like poverty
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Joined: Feb 2001
Posts: 4,086
Campfire Tracker
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Campfire Tracker
Joined: Feb 2001
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....I had some .30-06 cases from a manufacturer they listed, and it over-annealed those, which required a couple firings before they returned to normal.
MD, I have brought a few back to normal by simply running the case necks back and forth into the neck portion of the sizing die and back over the neck and expander ball without removing the case from the die. At least that seems to work. Have you ever tried that? Five or six cycles, and the necks are back to where they should be. Ted G'day. How can you tell if brass is over annealed? Thanks. I tested the ones I saw by pressing the neck mouth with my thumbnail, and they dented easily. Five or six runs back and forth as stated above and they were firm again. Ted
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Campfire Outfitter
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....I had some .30-06 cases from a manufacturer they listed, and it over-annealed those, which required a couple firings before they returned to normal.
MD, I have brought a few back to normal by simply running the case necks back and forth into the neck portion of the sizing die and back over the neck and expander ball without removing the case from the die. At least that seems to work. Have you ever tried that? Five or six cycles, and the necks are back to where they should be. Ted G'day. How can you tell if brass is over annealed? Thanks. I tested the ones I saw by pressing the neck mouth with my thumbnail, and they dented easily. Five or six runs back and forth as stated above and they were firm again. Ted Work hardening via sizing/expanding. That's how new cases become harder (less plastic) during firing cycles, therefore annealing is required to return the case to an acceptable condition.
GOA
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Thanks, When I read through AMP's statement, I didn't see anything about full annealing versus recovery annealing - maybe I missed it. I just noted the lab tests that measured the degree to which the brass was effected by the two methods. Is there a short version of what is the distinction between full and recovery annealing? Which of those two is being accomplished by the candle anneal method? Thanks, Rex
They don't mention anything specifically about the differences in their articles that I know of but I haven't looked at their website in a while. In a nutshell, there's two basic mechanisms that effect the hardness of the case, it's grain structure and defects within the atomic lattice. There's 3 phases in annealing, recovery, recrystalization and grain growth. During recovery, which is what you're doing when keeping temperatures relatively low (750 tempilaq, SBA, etc), enough energy is applied to remove dislocations within the atomic lattice. That moderately softens the case but retains the strength of the cold worked grain structure because there's no recrystalization/grain growth. Heating the case to higher temps (or longer times), causes the grains the recrystalize and grow back as large strain free grains. That's what yields the large reductions in hardness (increase in ductility) but at the expense of a weakened material. Unfortunately I get up at 2am for work so have to leave it at that but hopefully that gives some insight as to why there's a disconnect between what AMP claims and the experience of users of other annealing methods.
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OP
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Elvis,
Basically, the necks are too soft. You can feel it when seating bullets, and accuracy usually ain't great--but if accuracy improves after the first firing, then you're pretty sure!
In the instance I cited, a rifle that usually groups 5 shots well inside an inch started shooting 3-shot groups over an inch. After the first firing, things got back to normal.
As has been discussed earlier, heating brass to 800 degrees F. for a few seconds does the job. Heating it hotter and longer can make it too soft--which is often what happens when heating it "red hot," however that is defined or perceived. Thanks MD.
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Campfire Tracker
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Campfire Tracker
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....I had some .30-06 cases from a manufacturer they listed, and it over-annealed those, which required a couple firings before they returned to normal.
MD, I have brought a few back to normal by simply running the case necks back and forth into the neck portion of the sizing die and back over the neck and expander ball without removing the case from the die. At least that seems to work. Have you ever tried that? Five or six cycles, and the necks are back to where they should be. Ted G'day. How can you tell if brass is over annealed? Thanks. I tested the ones I saw by pressing the neck mouth with my thumbnail, and they dented easily. Five or six runs back and forth as stated above and they were firm again. Ted Work hardening via sizing/expanding. That's how new cases become harder (less plastic) during firing cycles, therefore annealing is required to return the case to an acceptable condition. Exactly, and that’s also how you can restore necks that have become too soft from being heated too hot. Ted
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Joined: Jul 2012
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Campfire Regular
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For example, the AMP article is based on their a priori assumption that hardness testing is the only true measure of the results of annealing.
That assumption is interesting, but it's conjecture and certainly not a well established scientific fact.
Ideally, for the purposes of a cartridge case, one wants brass to maintain a certain hardness. The problem with work hardened brass in that application is not necessarily the increased hardness, but the loss of ductility and potential development of stress fractures.
To simply maintain that Salt Bath Annealing has no effect on brass denies the actual results of actual users experience.
They don't claim that hardness testing is the "only true measure of the results of annealing". It is however a good measure, and a Vickers microhardness traverse is a particularly good method for assessing the extent and consistency of annealing along a sample. It is widely used by metallurgists, and I've personally done lots of them for this and related purposes. For a given sample of cartridge brass, as we anneal hardness drops and ductility rises. As we cold work, hardness increases and ductility drops. They are opposite sides of the same coin, so hardness testing is a really good proxy for ductility in this particular application. The authors of the article didn't claim that salt-bath annealing had no effect. Their results were that it did not adequately anneal case necks, even where time and temperature were such that case shoulders and body were over-annealed. They also point out that it is hazardous. Nor did they claim that their machine is the only method by which cases may be annealed. This is a straw man.
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The Scientific Method is based on making intentional wrong assumptions and testing them, and learning from mistakes.
Changing theories as needed to accommodate the results.
That IS the scientific method...based on observation of the results. You need to reread your Karl Popper and Thomas Kuhn. Or perhaps just read them the first time. Worth reading too.
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Campfire Tracker
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I've always used a drill and propane torch and decided to give the candle method a try. I needed to size 50 rounds of well used 223 into 222 Rem, with the candle method I was getting wrinkles and fold when moving the shoulder on about 50% or more cases. I went back to the torch and the ruined cases dropped significantly. When annealing for case forming 9.3x72R to 6.5x58R Sauer sometimes I have to anneal two or three times before I can get the case formed. 9.3x72R right to 6.5x58R Sauer center.
Last edited by erich; 04/16/20.
After the first shot the rest are just noise.
Make mine a Minaska
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