S&F. I think my previous reply might have confused some. The action is undoubtably a magnum mauser. At some stage the extractor has been replaced for some reason (broke, damaged). The stripper clips and rear bridge are original unaltered magnum mauser. Note the postion of the thumb cutout.

Compare with a lengthened standard mauser (I have some photos somewhere, but pleanty abound) and the difference is immediately obvious.

Magnum length extractors are available, I think even Midway lists them.

Cheers, Chris