This is going to be "old news" for a lot of you. I did about 30 minutes of scouring CB's for something close to what I've discovered about Winchester LRP's going into "CBC .500 S&W" brass. Started bench priming some CBC brass with Lee turret press using Win. LRP's and they dropped in way too easy. Anyway I only primed about 5 or 6 and decided to get the CCI-200's. Lo and behold, that familiar resistance was back so I used those after decapping the few I primed with the Winchester.
So then I measured both the Winchester and the CCI and sure enough there was a .001 difference in diameter. I DID test the Winchester with a Star-Line case and it fit snug. I seemed to remember somewhere I was reading that "CBC" brass in general have slightly bigger pockets. I don't take any chances with "anything" coming loose with the 500.
Winchester LRP
CCI-200