Great pictures!

Oops, I should have noted that the mag I showed is actually modified a little to try to accomodate the slightly bigger 6,5x55 Swedish Mauser. It isn't my rifle, but I've seen it as it is for sale at the moment (and the picture is from an article about MS rifles in general which features this specific rifle). Despite the altered magazine the rifle can still only feed 4 6,5x55 cartridges, and also only one type of handloaded cartridge with a certain bullet length. Other types of cartridges will not feed.

The post-1950 models added wings on the side of the magazine (can't find a picture of a 1950 magazine) so the cartridge recess didn't have to be so cartridge specific, which probably lessened the handiwork of producing support for a lot of different calibers.

Tried to take a pic of my NO model magazine, which is exactly like the 1950 one:

/C

EDIT: Added pic