We can uniformly turn case necks, ream to a standard primer pocket depth, deburr and standardize flash holes, clean cases, brand sort, neck or full length resize, weight sort and even anneal necks.
My question is would you expect cases (30-06 class) that are treated (processed) the same and are weight sorted matter in accuracy when of different manufacturer?

Good question!

I think it depends upon the true internal volume vs weight as a determining factor. Additionally, the actual force required for bullet pull I think might vary slightly regardless of dimensional uniformity. Alloy variance and actual hardness or resilience.

All that BS aside, may I be good enough to shoot those differences and be able to quantify them.

I might worry about it if I suffered from OCD, was anal retentive, and liked to split hairs.

One would think that if they weighed the same they would pretty much have to be the same. I mean the outside dims would be the same so the only variance would be in the case wall thickness. If one were really interested, it would be simple enough to run a little test and see.
Shoot 10 shots with brass from a single manufacturer that had been "processed" the same and had the same weight. Then shoot 10 shots with mixed brass from two or more manufacturers that had been "processed" the same and weighed the same.
After having done that, get back to us.

I find it easier to just stick to one brand of brass. No, Virginia, I don't weigh cases.

There could be differences in the web construction. It's easy to check case volume. My hunts are too few and far between, and some are costly, a lot more so than brass. I like to start with 100 good quality cases, like Lapua, Norma, etc. That being said, I am reminded of the old Indian.

He shot his moose every year with a 30-30. Only had a few cases. Knock the primer out with a nail, poke in a new primer, squeeze the neck enough to hold a bullet, fill with powder and good to go another year.

absolutely !! roger

For every seven to eight grains of case weight difference there is one grain of powder capacity difference if the outside dimensions are all the same. If they have all been sized, trimmed and otherwise prepared the same the if they weigh the same the should have the same internal capacity.

The internal cavity may be shaped differently but it will have the same internal volume.

Definately. Wouldn't do it if I wanted to shoot bugholes. The variation in case weights has apparently been found to often be in the case head and irrelevant for the purposes of volume (Zediker as I recall).

If the outside dims are the same, how could variations in the case head not affect volume?

The rifle chamber has a volume running for the bolt face to where the bullet seals the bore. Any difference in weight/mass placed in the volume changes pressure/velocity. I want all the same lot number of brass.

Are you saying that those two pieces of brass would weigh the same? It certainly doesn't look like it. That was the whole point: if the brass had the same outside dims and weighed the same, shouldn't the volume be the same and could the two or more separate brands be used together.
I've known hunters that certainly weren't accuracy freaks that paid little attention to head stamps and managed to kill a lot of stuff. For myself, just to see, I deliberately used mixed brass for some target shooting. The results wouldn't win any prizes but it was certainly accurate enough for hunting.

No not saying that, but if they were the same, brass in different areas of the case may make a difference. Compare thin neck walls to thick. This has a large effect on accuracy & the rifle does not have to be a "tight neck" to see a difference.

We get our brass in bulk, and all of it goes through the following operations before it is used.

1. Visually inspected and sized - sometimes we find the odd one that has faults on the neck, shoulder or body.

2. Trimmed.
3. Primer pocket uniformed.
4. Flash holes deburred.
5. Weighed.

We sort them by weight, depending on the quantity we have, and caliber involved.