Salt Bath Annealing Doesn't Work! by AMP

that doesnt match up with what i have seen. i have seen a case get 'work hardened' after a few times being fired, not just after one. and by that i mean the neck splits or its hard to resize.

or am i missing something?

I imagine there is a substantial amount of variability depending on which cartridge you are firing, and how well it fits your chamber. Fire-forming might increase hardness significantly while firing a tight neck-sized case might be minimal.
 
It brass vickers hardness increases in steps and then flattens off - depending on where the case started in terms of hardness.

At what point its too hard and starts cracking etc depends on the myriad of factors.

The point was if you want "consistency" then a "fire once - anneal - repeat" may give you that... repeatable consistency

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Awesome articals,,, this is one of the best threads todate on the subject by far...

A deffinat learning curve for all the different ways to look at this...

My old adage to this by not annealing was the size all my cases at one sitting,,, I found that I'd get my most consistant neck tension across the board,,, but I can see that as time passed that you the necks were starting to stiffen up over the life of the brass...

I hope """ if""" I jump on this band wagon,,, that I feel more consistency over all,,, I'm thinking that this might be the situation...

Only time will tell...
 
I found it interesting that the brass chemistry from Lapua did not meet the SAAMI spec for chemistry percentages. Makes you wonder how much all brass varies, for initial work hardening, chemistry and a response to different controlled or less controlled annealing processes. Bucket loads of variables that may never be reduced. Do what works for you, safely, is all I can say.
 
Member "Slick8" could answer that better than I could so I'll leave that to him. I mailed the cases to him just a little while ago....
What temperature was the salt? and for how long did you dip it?
I did an experiment using a temperature crayon that melts at 482C.
I had the salt at 550C, and used 224 Valkyrie cases. It required 8 sec to melt the crayon, which is above the salt level, so I estimate at least 6 sec is needed.
I'm going to do the same experiment with 6.5 Creedmoor and 336 Lapua Magnum, and expect a longer time.
 
If the information presented by AMP was accurate and not flawed in some way, I am surprised that we are not seeing online reports from Shooters expressing their negative findings. Heat transfer is a function of material, temperature and time.
 
If the information presented by AMP was accurate and not flawed in some way, I am surprised that we are not seeing online reports from Shooters expressing their negative findings. Heat transfer is a function of material, temperature and time.

IMO AMP is attempting to build anti salt bath sentiment likely because it's cheap, repeatable, and a big threat to sales. There are enough people looking closely at the salt bath that we should see some independent testing here in the near future. Confidence in a process is paramount to confidence on the range. In that respect, AMP was very successful.
 
Salt bath will not go away based on the current usage and in principle. Optimization would be a logical derivative of the shout out from AMP. AMP has pushed the optimization of the salt bath process. Always good to have different ways to skin a cat.
 
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