Can rimmed cases give the most accurate headspacing?

[Grimstod]

Rimmed cases for factory ammo product better headspacing. In my experience. However if you have custom dies and are bumping back the shoulder only .0005 then rimless seams to do better but then again you can headspace off the should with a rimed case too. I actually do this a lot with my own 54r wildcats.
Headspacing a rifle for a rimmed case will mean that you must also use just one brand of brass. For example I have a 54rImproved that will only take Lapua brass. Stick in winchester and the bolt will not close .

 

[kountryboy2]

Gary, I have about 100 loaded rounds, 100 once fired brass and 1 box of new in the old sealed Winchester-Olin plain box.

Butch,
If Gary doesn't want them I'll take the once fired brass and the box of new brass.