Home Forums Hunting & Shooting Ask The Gunwriters JB - Annealing with Candle, Too Much?

Fück science.

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?

You need to reread your Karl Popper and Thomas Kuhn.

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.

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.

Thanks MD.

Exactly, and that’s also how you can restore necks that have become too soft from being heated too hot.

Ted

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.

Or perhaps just read them the first time. Worth reading too.

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.