As Issued 1944 IBM M1 Carbine

[BrianQ]

To change the subject away from the rear sight for a minute, is that cut across the barrel just behind the front sight a bit unusual for an IBM barrel? Also, I can't help but wonder, with the many thousands of parts that were integrated to IBM from several of the prime contractors, wouldn't it be a bit unusual for an IBM carbine to have all IBM marked parts? Isn't that sear a bit early for that serial number? Maybe it turned up at the bottom of a bin just as this one was being assembled? I only have one IBM, and it's got and NPM trigger housing, Inland bolt, and a Niedner front sight, but it could have been built that way. - Bob

The " cut across the barrel just behind the front sight" is found on all IBM made barrels.

Published integration records show roughly 465K parts were integrated to IBM. IBM delivered 346,500 carbines. If you take that info at face value one could claim there was no such thing as an all IBM carbine. However, when you start looking at the parts that were integrated roughly 200K of the 465K were parts you could not identify as being made by or for a specific manufacturer, parts like springs, pins, screws, etc. Discounting the non-identifiable parts the percentage of integrated parts to carbines delivered gets smaller. Period records also indicate a lot of integrated parts were used to fulfill the spare parts requirements of contracts in addition to being used to assemble carbines.