OHHJIMMY,
I can't improve on ShortStake's comments except to answer your additional ones. Since BPCR shooters are not interested in a fast follow-up shot and generally keep and reload all cases, when Browning designed the BPCR line the automatic ejector was removed and replaced with a simple extractor that slides the case or unfired cartridges sufficiently out of the chamber to be fully extracted by hand. There is no cartridge diverter.
Concerning the scope base mounts, Iowa's comments are correct with the additional caution that shimming will most likely be required under the Weaver bases. In fact both of the noted Weaver base packages contain the note, “SHIMMING IS PROBABLY REQUIRED FOR PERFECT SCOPE ALIGNMENT”. I confirmed the Weaver bases will fit and shimming is definitely required when using standard Weaver rings. When mounted on my .40-65 Browning, shimming totaling 0.038” was necessary under the rear base for perfect scope-to-ring alignment. Weaver style Burris Signature Rings, with synthetic pivoting inserts within a steel outer ring, will eliminate the need for shimming, assuming the scope has sufficient adjustment range to compensate for the slight tilt. Better yet, use the Burris’ Signature Pos-Align Offset Insert Kit to eliminate both shimming and scope tilt. Hope this helps.
Wayne