Does anyone have an Irwin-Pedersen carbine with the serial number between 17778xx and 17905xx? This is the serial number range of the receivers which I suspect were made by Saginaw at Grand Rapids.
Bruce, I suspect the first 15,000 serial numbers were used by Irwin-Pedersen. Who knows how many receivers successfully made it through heat treatment, inspections, etc. and were used in production. there are plenty of examples of S'G' marked receivers with serial numbers in this range. Those were undoubtedly re-used serial numbers.
The second, roughly 15,000 serial numbers with the Irwin-Pedersen name stamped on the receiver may have been actually produced by Saginaw after the takeover.