Brian, check out this spec from SAAMI:
http://www.saami.org/PubResources/CC...Winchester.pdf
It shows that case length spec is:
2.015" -.020" (from 1.995" to 2.015")
50.18mm -.51mm (from 50.67mm to 51.18mm)
Note that SAAMI specs are voluntary; it's up to manufacturers whether or not they go along with it.