Buckstix, I find that serial disparity interesting too, and I would have agreed with the setting aside of an action, if it was an old action, however this receiver is roughly a 1940/41 Astrawerke made piece. It is not marked on the sidewall as yours is, but rather on the barrel in 2 or 3 places IIRC, including the intertwined “ASS” trademark. It has some definite similarities to your rifle, for one, the mag well is cut out of the aft end completely, like yours is, to fit the 8x68. In general it conforms to the typical 1940’s style from Schüler and is fit with a Röchling barrel.

Looking forward to your progress with the 11.2 that’s another dream gun! Keep the updates coming please.