OK Guy's I couldn't stand it anymore, I know all of the 3 drillings that I have 1 has the tighter chamber. I just came down from the loading room where I measured 3 factory rounds from different manufacturers.

Norma (old)

Rim dia. Base dia. Neck dia.
.477 .428 .382

RWS (old)
.482 .428 .385

Selleir & Bellot (New)
.482 .424 .385

Hope this helps, if trouble chambering try to find some of the older norma 10 rnd boxes Red label, they seem to work fine in my tight chambered gun and are so marked after firing for reloads for that gun since they are now fireform to that chamber.

m4220