I tend to agree with every thing that has been said. As to a case being more accurate than another, this maybe the case. No pun intended. What I mean is that one case design might produce a better and more even burn rate, primer flash hole size etc. What sort of difference at the target this makes may be measurable and it might not.

I know that with my 6.8SPC the Rem case with large primers and flash holes are definitely not as accurate as the Hornady cases with the small primers and small flash holes ( this was tested with several different bullets and 2 powders). Would this be the case in a different 6.8SPC rifle or a different cartridge, I have no idea.