Herbert,
The receiver is evidently cut for the "short" blade extractor. I had not previously assembled all the parts since the receiver was purchased alone with no other parts from S&S Firearms. I had simply presumed they had stripped it for parts? But upon installing the "long blade" extractor tonight, I discovered the action would not close as the long blade is too long. The "slot" appears to be cut such that the blade does not quite reach the top face of the receiver but stops within the chambered portion of the barrel. Whether it was actually completed as a rifle, judging from the crisp condition of the edges, I would think so. Lose receivers don't store well and tend to attract "handling marks" over the years that are not present on this specimen, least not the exposed edges that would have been protected by wood or metal. The case finish is largely gone, but the swirling flow of the cast steel is very pronounced almost as if to make it look like a wood grain. It had been my intent when it was purchased and had in fact discussed the planned rebuild with Larry Romano, of restoring it as a sporting rifle but in a custom "take-down" variant. But later decided to just copy #1325 instead. I have chiefly used it for 3D modeling, and have given some thought into perhaps replicating the receiver using a 3D printer.