Some plausible info. came my way and was re-sparked by an email I received from the previous owner of the MSch rifle I have.
His email tells me 'he doesn't actually remember firing the rifle' it was to be a project for restoration..but when he got the rifle home, thought it 'too nice to meddle with'.

RigbyMauser's comment -Quote-:'All Mannlicher Schönauers at that time they were made were litterately a handfitted gun. I suspect from your description some former owner had lost the original Rotary steel magazine and had it replaced with another one. However they hadn´t done what you did. Used the time to grind angles on the feedingramp so the cartridge could cycle perfectly.
So to your Question. No..a rifle from Ferdinans shop would never had left without a Meister Büchsenmacher prüfung. Nie!' ....and my thoughts the rifle wouldn't have left the factory unable to function correctly led me down a slightly different path, particularly after I'd seen photo's of later rifles with a different feed ramp profile..similar to the form I re-shaped mine into.

I now think the rotary magazines that we know are 'cartridge specific' were machined with different shoulder ramps on the magazine rotor blades themselves and so, if too shallow, as on later magazine rotors, would be unable to raise the feeding cartridge high enough to access the older style of feed ramp.

So it seems possible a magazine switch either knowingly or unknowingly by unknowledgeable staff at a dealership, could easily result in this problem which would not be apparent - until feeding rounds from the magazine using the bolt.
This would occur leaving absolutely no evidence of wear or other possible reason for the malfunction.

Just my thoughts from all the information I have available.
Cheers, deeangeo