It turns out, I have no idea what I'm looking at with a borescope. Cool toy and all but yeah. The timing was also unfortunate as I was shooting up the last of my factory .338 ammo when this happened, and I have no intentions of buying anymore.
I took a guess and loaded up 30 rounds in new Lapua brass with 285eldm's and a grain under max load of Retumbo. That averaged just under an inch. I would assume I can bring that down where it belongs with load development, but I haven't had a chance to do that yet. That's why I haven't updated this post.
I did talk to customer service right after SHOT, I had a direct # from emails when I first bought the cans. That call was pretty neutral. They said that this was an issue they were aware of, that it was limited to a period of production and that they now take measures to prevent these from going out (cutting a number of cans in half out of each batch to check for debris). I asked for nothing and they offered nothing. They said to reach back out if I did have issues with the rifles.
The Hekate cleaned out fairly easily. The Hyperion on the other hand was packed with what must have been ounces of hardened material and it took a significant effort to remove it all.
No NDA for me. I'd rather inform the community than have a new barrel. It would be pretty tough for me to prove any degradation in accuracy anyway, I don't have any way to authenticate a base line prior to the damage.
I will get to load development soon hopefully.