Stan, I've built rifles on both extractor and ejector actions. it really doesn't make any difference, although, being a dyed-in-the-wool reloader, I prefer the extractor.
Skeettx, thanks for posting the photo of the 8x57JR. It hadn't even ocurred to me that I have a Simson Cape gun in that calibre, along with lots of ammo for it. Rim, base, shoulder, and OAL are almost identical to the 6.5x57R so it gives me a measuring tool to work with until my brass shows up.