Rodell,
I suspect your AMP annealing was too much for that particular batch of cases, making the necks too soft. I suspect this because I played with an AMP extensively a couple years ago, with generally very good results--except with one particular "brand" of .30-06 cases. I looked them up in the list the AMP people provide, and used the recommended setting. The same load that rifle had shot very well for years results in lousy accuracy.
I contacted AMP and they weren't partocularly helpful, so I figured it out on my own--I think. That particular batch of brass was around a decade old, and the company that sold it was not making their own brass. Instead they were buying brass from some factory, headstamped with their brand. I suspect the batch that AMP listed was from a later batch, which may have even been made by another company--though I have also seen brass made by the same company vary considerably.
Anyway, after that bad first firing, the brass work-hardened up just enough to go back to work very well again. Many factors can affect bullet "pull," and too-soft annealing is one.
