So, I’m just gonna throw this out there for contemplation. In about 2008 - 2009 I spent time in the shop in Ilion. The guys there were very nice, knowledgeable, bend over backwards to make things right kind of guys. While there they were frustrated that they were tasked with the sporting line QC comebacks. As part of all that was going on, they had regular barreled actions that were at their disposal to fix issues with regular line products. There was little custom work going on at the time, and they had no tooling to make .224 barrels any longer. Now, these barreled actions that we all bought may have been ear tagged for the custom shop, but for what purpose? I do not believe mine were crafted in the Custom Shop. As far as what I know, Custom Shop barrels were button rifled, not hammer forged. Bore scope a 40x compared to a 700BDL or anything similar. You can see the advance marks in a hammer forged barrel.
About other things mentioned, in the regular factory you could watch the red hot ingots come out of a furnace and go into the hammer forge. They did not like visitors to stay there long because the ingots and furnace were hot as hades, and the hammer forge very loud. Although I watched this process on two occasions, I never heard or knew that the chamber was partially formed there. It very well could have been. I just did not notice or ask that detail. I also missed the chambering process in the regular factory somehow.
I think it bears mentioning that the Mike Walker Custom Shop, and what it was over the many years thereafter, ebbed and flowed in terms of what their primary tasks were. Obviously they were controlled by upper management. I’ll say it again, the guys there were super, Aces in terms of customer satisfaction.
Just observations at a snapshot in time.