AMP Aztec codes evolving over life of brass?

[LVLAaron]

I'll check a piece when I get into the shop tomorrow. I have a batch of 308 srp brass that I've reloaded 30+ times.

 

[Webster]

Hey Guys,

I have some 6mmGT brass I'm prepping after shooting a match earlier today. During this brass prep session I randomly decided to reanalyze a piece of fired brass because the code I'd generated after the first firing (131) seemed lower than I would normally expect.

The new code read out at 143. I decided to sacrifice another case, and it came out 144.

I'm planning to anneal this batch of brass at 143 going forward, but I'm curious what I should make of this?

The first code I received from the machine came after the brass had been neck turned, and once fired. I weighed cases and Aztec'ed a turned/fired case per the instruction. This is basically my process for all my brass, and really haven't thought twice about it until now.

If you're using bushing dies, and AMP annealing, are yall reanalyzing brass after several firing/sizing cycles (i.e. once the unsized portion of the neck has had a chance to thicken up)?

Thanks,
Mike


Edit: I should add, this brass hasn't been shot a lot. Maybe 3-4 firings at most.

Does anyone know how the Aztec codes are determined? The only thing I can think of is that the currant draw is measured and compared to a table of some kind that relates currant and time to some data that was determined by actual hardness testing. It cannot measure hardness and I doubt it measures temp.

 

[dgeesaman]

Does anyone know how the Aztec codes are determined? The only thing I can think of is that the currant draw is measured and compared to a table of some kind that relates currant and time to some data that was determined by actual hardness testing. It cannot measure hardness and I doubt it measures temp.

My best guess is they run until the current starts to fall as the neck disintegrates. Then they interpolate a setting that will get the brass to a temp well before melting.

David

 

[Webster]

My best guess is they run until the current starts to fall as the neck disintegrates. Then they interpolate a setting that will get the brass to a temp well before melting.

David

Looked up how the conductivity of copper changes with temperature. Many articles with a Google search.

The conductivity decreases with icreasing temperature. It would seem that as temperature increases it would change the current draw in a predictable way. So the Aztec codes must be derived from this relationship. Need to look up if brass is different than pure ccopper.

1. How does the conductivity of copper vary with temperature ...
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   www.quora.com › How-does-the-conductivity-of
   Copper is a metal whose conductivity mostly depends upon the flow of electrons as compare to lattice vibration within the copper and this is the main cause of thermal conductivity of metals, but as we increase the temperature of Copper, lattice vibration increases which create hindrance in the path of electron due to which energy carrying by the electrons will get decreases and hence thermal conductivity of copper and other pure metals decreases on increasing the temperature.