Interesting, unusual, exotic and a very nice rifle. But little practical purpose. Maybe some rajah had a bolt action in the .425 WR and wanted a double in the same. Or was a WR devotee.

As said the .450/400 rimmed cartridges existed. Nowadays the .500/416 NE and .416 Rigby NO.2 exist, both rimmed.

There is a reason why rimmed cartridges are recommended over rimless cartridges and a rebated rim seems to double those issues. Complexity increases the chances of failure.

Nice rifle though and a collector's piece.

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I like the idea of using clay targets at shorter ranges, say to 50 yards or 65, 75 yards. If one can hit them with either barrel from a field position, or a field rest, sticks etc, both the regulation, accuracy and also shooting skills are well adequate. Dinner plate at 100 yards again from a field position or field rest.

A dinner plate at 100 yards allows shots at big game, and also medium game, to that range. 150 or 200 yards would be better of course.