Howdy KK and welcome.
I'm not sure I understand the description of the jam. Are you ejecting slowly, or with force. Since there is only an extractor and no ejector on a '73, the carrier acts as the ejector, hitting the bottom of the brass casing and kicking it up and out of the extractor hook. Going real slow can make it hang up a bit. As for the shape of the carrier top, I have heard something about them coming with some shaping to make the cartridge kick off to the side (although lots of Mirokus throw them forward). Maybe it is related to that. There are other Miroku owners around these parts so I'm sure one of them can tell you how it compares to theirs.
That is some gorgeous case coloring! Does it have nice wood as well?