captaalloway-
Welcome to the forum!
I would use the CCI 400 primers without second thoughts.
Hornady and Western Powder Co. used Winchester Small Rifle (WSR) primers in developing their published data, and I'm not aware that there is much difference between the CCI 400s and the WSR primers in terms of "strength" of ignition.
If you haven't already looked at it, a careful study or small rifle primers has been posted here:
Small Rifle Primer Study. The work is a half-dozen years old, but I don't think there have been significant changes in the primers since then. The lengthy background in the article is interesting too.
Hoot evidently confused the CCI 400, a standard SR primer, with the CCI No.41, which is the mil-spec ("hard cup") version of the CCI 450, a magnum strength SR primer. I'm not sure why Lyman used them in doing their loading data development. I've used the No. 41 at times, mostly because I had them available and left over from other work. The CCI No. 41 and 450 primers, along with the Rem 7-1/2, may be called for when using some ball powders known to be more difficult to ignite, or if shooting in really cold weather. If you stick with the published loads there should be no difficulties in using the CCI 400s. If you do experience any problems, it will be helpful if you will describe them on the forum.
Thanks.
-- Bob