I'm wondering if one of the custom expanders from BACO could solve this problem...maybe a .405-.408" expander.

I know it may not make sense but the thickness of the case mouth are the same as the others....009".

With a.408 reamer?

You'll have to pardon my ignorance a bout outside neck turners but it seems the problem must be on the inside of the case. Why not just ream the inside? The problem with that is I have a Forster trimmer that a reamer would work well with but they don't have a .408 reamer, just a .400 and .410. RCBS has one but you have to buy the die at over $100 plus another $50+ for the reamer. I only paid $40 for these cases and it wouldn't be worth it. I wouldn't know what to do with a lathe if I had one.. Last time I used one of those it was in  high school shop and it was a wood lathe.

I think in light of having just gotten 150 Krag cases I'm going to sit these aside for awhile. I've had the 38-55 cases bulge a little with the expander die but noting that would cause cambering problems. The problem with the dies with that one was the size die sizing down too much. Maybe an RCBS or Redding size die would help in this case, I don't know.

Forster doesn't make one for .40 caliber. Their outside turners only go up to .375".

You're right, I'm prone to do that. I recall only once did I have to use an inside reamer. I had a 7mm Rem Mag in a 700 BDL back in the early 70's that gave a problem after a couple reloads in the neck. That case has such a short neck brass would flow and I wouldn't be able to get a bullet back in the mouth without reaming the necks.

I checked capacity out and the Shiloh brass gives less capacity than the BACO brass by about five grains. Measuring a 60 gr charge of Swiss 1.5 in both cases the level is not the same and I had to trickle out about five grains from that case to equal the same capacity as the other Krag cases. Apparently that brass is just thicker further down than I can measure and compare.

I have more than enough Krag cases now to get started and have some to spare so, I think I'll just use those. I had hoped to use the Shiloh brass as if nothing else, it was refreshing to see the caliber stamped on the head of the cases and the rim fits right up flush with the chamber. The Krag brass leaves a bit of space by a few thousandths.