I'll bump this up and add some more commentary on things I've found.
One, Federal must have bumped up their head thickness as FC headstamp stuff I've picked up at the range are running over 0.190" and up to 0.205". I still check everything, and since I don't sort out once fired from 5th fired, check many several times. Before getting into the little black rifle scene .223 reloads were for the wife's Mini 14. To keep the ejection distance down they were loaded pretty light. The Mini still cycled fine.
These light loads don't cycle our ARs though so a little more attention is necessary as the load goes up.
Case stretch seems to be an issue with extended case usage. While I have yet to find a case with a pending separation from internal erosion I pick the likely ones and look inside. Man, these .223 cases are tiny

Was hoping to have some good pics to show, but I found nothing really significant.
Use Google to find better pics with cases that were ready to break.


But, anything even close to bad is culled out. Hey, they're range pick ups.
Another thing that I've found is the mil vs civy case weight you hear about, or that this brand is more consistent than another. Well, All that internet talk is mostly hogwash. Sure, the majority of one brand might be centered around one case weight, but the high and low extremes are popping up in just about every brand I have. Somewhat large ranges in weight. Sorting by brand doesn't eliminate the outliers.
(I know, RV talking weight sorting again

)
Here's the results of 50 processed cases. Sized, trimmed, primed.
5 weight groups of 10 cases were charged with CFE223. Full case, tapped down, carded.
I picked one light and one heavy and checked water capacity. Results with the powder and water were pretty close. The values listed are the average of 10 cases (except the water weights)
If the weather ever improves I'll take some light ones and some heavy ones and see just how much the volume effects velocity.
223 Case Wt Vs Vol (CFE223)Primed Case Powder Water
94.0 32.37 30.40
96.6 31.92
100.0 31.45
104.0 30.42 28.64
Went back and checked the water vol data I wrote down and the 28.64gr. water might have been with a 108gr case. The powder weights are correct, I think. I'll go back and try it again with the water.
What I've noticed with published data is case volume, sometimes volume with a seated bullet is given, but for a 'Brand' of case, not case weight.
You can look up advertised case volume for different brands, but I'm guessing that's just a process average. The capacity really seems to closely follow case weight.
The "drop charges about this much for Mil cases" doesn't hold water if the case weight range isn't known.