Annealing Lot to Lot Variation

Just wondering how much lot to lot variation guys are finding when annealing with an AMP annealer. I've only had mine for about a year and only have experience with two calibers that I have two lots of brass from the same manufacturer for each caliber.

One is a 300WM with two lots of Hornady brass purchased a few years apart, the other is Lapua 243 brass purchased withing a few weeks of each other. In both cases, the Aztec produced anneal code is the same.

This is an extremely small sample size, so I am wondering what others have found and if you skip destroying a $1+ piece of brass each time you switch lot numbers? Even if the generated code is different by one count, how much difference does it make?

I have also only had my AMP for about a year, so my sample sizing is also small. However, I have seen a different Aztec produced anneal code, when switching brass lots, every single time. Again, this is maybe only a sample size of 3-4 lot switches.

I've also seen it produce a different code on the exact same lot of brass on subsequent test. For example, the first time I tested a lot of brass it produces code X, then that brass is loaded, shot & I've tested it again (just out of pure curiosity), and it produces code Y. I'm not sure what to make of this, but I'm sure someone with more knowledge will come along.

Depending on your batch weights/neck thickness spread, you will see differences in the AZTEC results.

Thicker/heavier takes more, thinner/lighter takes less.

From there, the above clip was from AMP's instructions and shows the rough figure for what you would get if you did a micro-hardness test and saw the results in HV per code step.

Sone day if you have your fine scale and a batch of brass in front of you, weight sort the batch and isolate the heaviest and the lightest and note the neck thickness (and seating force if you can). Roughly speaking for something like a 223 case, if the spread is at least 3 grains, then you will begin to see a difference in the codes. The significance of those values is described in the clip above.

From that basis, you would then take a sample of the brass at those two extremes and test the seating forces to see if you like them or test them on target and see if they affect you.

ETA: AMP will take questions and answer them pretty quick. If you want to hear it from the horses mouth, send them an email.