Salt Bath Annealing Doesn't Work! by AMP

[Don A Parsons]

I'll update my findings on un-annealed brass this week... 3800 shots fired and counting on 200 peaces of Lapua Palma Brass...

More time shooting then F@rting around with all this waited prep time...

Ha... Close range stuff under the 1000 mark,,, of course some of it falls into the 1400 and 1700 meter stuff.

Cheers from the North

 

[NEMTHunter]

The reason for annealing brass is to soften it. It works trust me. When you spend time necking down say from .416 to .308 you find out real fast how well annealing works and if you did a good job or not.

I always quench the brass I anneal. It works. I can take brass that hard to neck down and buckles and just does not do it easy to after annealing and quenching it necks down simple and easy without buckling. It works.

 

[J E Custom]

At first when i read this article, I thought it might be a product war.

Being somewhat a metallurgist and having experience with hardness test of all kinds, I found it to be very detailed and well done. the results were also well documented and I believe It to be a valid test.

I did a similar test on new factory brass using the Brinell hardness test method because it is more commonly used for softer materials and much cheaper. with this test I discovered that many of the new factory cases were never annealed as the last step to save money like the after market cases are.

https://www.hardnesstesters.com/test-types/brinell-hardness-testing

I don't own a salt bath system so I personally cant attest to the quality of the anneal and only testing the system myself would convince me one way or the other. I did question the max temperature used but thought time could render this temperature good enough.

There was a mention of water quenching and I water quench all of my cases for the most consistent anneal. The reason is simple, it stops the anneal in the same location of the case, cases that are allowed to cool normally will be annealed, but based on where they land or the temperature they are annealed the annealing softness can migrate farther back and be at different positions on the case. Consistence is the name of the game for quality annealing.

I know people that have and use this system and can only recommend that they have some hardness test done to verify the results of their annealing.

J E CUSTOM

 

[brian b]

I forwarded that article to Gary at Ballistic Recreations. I'll be interested to see what kind of response I get (if any).

Very interesting article, I like how they worded it "Executive Summary"
Obviously salt bath annealing has put a dent (pun intended) in AMP's business. I have used salt bath and it seems to work and is more consistent than the torch methods I have tried, obviously I don't have the testing equipment that AMP does but they claim salt bath is completely worthless.........I don't buy what they are saying as absolute truth. would be awesome to get info from a third party source that is not on ampannealing's or ballistic recreations payroll.

 

[Rick Richard]

I purchased the Salt Bath Annealing kit with the assumption testing was performed and verified for effectiveness. I sure hope so since I know a bunch of folks that have recently made a purchase. I sent an email to the company owner where I purchased the kit and hopefully he will respond.

 

[bigngreen]

The whole premise of the article is that there is a perfect hardness and to be of any value the method must produce results at that level. I guess I see the main function of annealing is to maintain a state of hardness across the life of the case which users of the salt bath method seem to experience. Don't know, interesting read but not sure of it's actual value real world!

 

[Mikecr]

I'm skeptical of their standard. For one, it's pure surface hardness, and based on factory brass (Lapua/Norma) as new. I don't know why that would be considered ideal.
We're dealing with ductility & hoop tension, and I haven't run across a correlation of these to mere hardness.
In other words, there may be more to it than one cherry picked standard.

I can also imagine that salt bath dipping is hitting AMP sales pretty hard.. So I'm inclined to believe pretty much anyone else before them.

 

[kyron]

One important thing to remember reading that article is who wrote it.

I don't care how good their material looks, it is still the same as bottled water companies paying for a study that says you need to drink 8 8oz glasses of water every day no matter what other liquids you consume, or the vegetable growers of America paying for a study that generates a "food pyramid" witch says you need to eat 12 servings of vegetables every day.

This is the company that makes the most expensive annealing system on the market dumping on the cheapest. And frankly looking at that data does not pass the smell test for me.

Data showing that you can get the entire rest of the case dangerously soft and still not soften the neck? When the heat source is at the neck? In order for that to happen you have to have altered the composition of the neck. It is possible that is what is happening, but that leads me to ask why they did not mention that.

 

[ar10ar15man]

a simple test is to seat a bullet.
in a new case
in a fired case...like 2 or 3 times
in a salt bath case
in an amp case
i can tell you there is a significant difference after i anneal with my amp

 

[kyron]

Well another simple test is to shoot bullets from the same cases. 10 times.
One set of cases anneal every firing.
One set anneal every other firing.
One set anneal at the beginning and after the fifth firing.
And one set anneal only at the beginning.
Compare chronograph data from the sets and targets.

It has been done. Check Bryan Litz's work.

 

[Dr. Vette]

There was a mention of water quenching and I water quench all of my cases for the most consistent anneal. The reason is simple, it stops the anneal in the same location of the case, cases that are allowed to cool normally will be annealed, but based on where they land or the temperature they are annealed the annealing softness can migrate farther back and be at different positions on the case. Consistence is the name of the game for quality annealing.

J E CUSTOM

Using the BenchSource, I do not quench. Every case spends the same amount of time in the flame, and they are essentially indistinguishable from another once they are done. If there is any difference in migration of heat it is miniscule, and more importantly not done at temps that would anneal the brass.

I suppose that I could have them drop into water when they leave the BenchSource, but see no need for it.

 

[J E Custom]

If everyone takes a step back and looks at the title of the piece from AMP they ask "if" it worked and the post title starts out with "IT Doesn't work" so right away I was skeptical. only after they concluded their test did they state that It didn't work. It is their opinion and based on there test results that was their conclusions. I personally don't like to say anything bad about a competitor and feel if you present your data and it is good most will sort out what they want to and come to their own conclusion.

I know people that use this system and are very happy with the results. The question that come to my mind is, does it do an adequate job and what is considered the correct hardness standard and not what one manufacture is. do we realy know what is best ? or just what works.

So I spent some time researching the Metals handbook and other sources to answer this question, if only for my self.
Here are the results of what one cartridge requirements were by the military for the M 855 cartridge case. This should be close/work for all cartridges.

Vickers hardness minimum maximum

Case head = 160 190
Web to body = 160 200
Back 1/3rd of body = 180 220
Middle of body = 155 200
Anneal Transition zone = 115 140
Shoulder neck junction = 95 125
Case mouth = 90 115

This would indicate to me that as long as you are in the range of minimum and maximum you should be good.

I'm not taking sides with anyone and I am only interested in the results. So take this information for what it is worth and use what ever system gets you there.

J E CUSTOM

 

[dok7mm]

A simple way to find out the validity of AMP's conclusion is for salt bath users to send some cases to independent labs for the Vickers testing. Or, you can keep on annealing by your current method, if you're satisfied.

I went from a Bench Source to an induction annealer (AMP) and I won't be changing, as my brass is far more consistent than I shoot.

 

[Wedgy]

Here are the results of what one cartridge requirements were by the military for the M 855 cartridge case. This should be close/work for all cartridges.

Vickers hardness minimum maximum

Case head = 160 190
Web to body = 160 200
Back 1/3rd of body = 180 220
Middle of body = 155 200
Anneal Transition zone = 115 140
Shoulder neck junction = 95 125
Case mouth = 90 115


J E CUSTOM

If I recall a Rockwell hardness test from Catshooter, Lake City 5.56 was the hardest of any case tested. What's good for military might not be good for our purposes.
As JE says, it's just info, make your own conclusion on what to do with it.

Edit; it does seem strange how a neck could not be annealed but the shoulder over annealed.