As Issued 1944 IBM M1 Carbine

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Originally Posted by rpw7351

We will never know.

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Ahhh, the last ditch defense, invoked after the preferred theory falls on hard times. Even if all things are possible, it is not necessarily true that they are equally likely.

I summarized info from a WWII order that could represent thousands, or tens of thousands, maybe even hundreds of thousands - of similar modifications. However many it was that got rear sights replaced, all (or almost all) would have shown both the chisel and round punch marks like our example here.

That's the big picture. More narrowly, you might want to find CCNL-345 and -378 which detail two late, late IBMs with factory adjustables. (Hint: they don't help your case)

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

If it helps Bob, I've seen that machined cut behind the front sight on more than a few IBMs.

I agree with firstflabn completely regarding the 10's of thousands, heck, millions of guns that have gone who knows where and will never be seen again for all eternity. I believe what we see now are some bring backs, presentations, a few possibly stolen from production lines or post war, many from DCM and LEO sales, and re-imports and foreign returns. I'm sure many of these were modified as per gov't edict. Many weren't and were declared "unserviceable" and sold. I'm more interested in the carbines built at the end of the bulk production runs. The ones that don't quite fit the preconceived notions, books or newsletters. Like the one in the previous post and possibly the one in this thread. If one looks at carbine production, there were the northern tier producers: Inland, Saginaw, IP, Rock-Ola, QHMC, Stan Pro, and NPM. From Michigan to Western NY. ALL near power, water, labor, subcontractors, and transportation. It would make sense that they would develop a local supply chain and swapping network that would be their primary sources for parts whenever possible. The same would apply to the southern cluster, Winchester, Underwood and IBM. SE NY and central CT. If we look at rear sights for instance (because of this tread). We have HI and H in Shield (Hemphill) PI (Packard) IRCO (International Register) CH (unknown to me) SA (Springfield Armory-post war?) and J.A.O. (J A Otterbein). We see T2 HI and H in Shield from Hemphill of Pawtucket RI as the first of the adjustables, I believe. Maybe because they were the first tasked to develop the adjustable sight? Packard came next to supply mostly Inland (PI) and upgrades. Next up, IRCO of Chicago IL to develop or produce the T3 (cheaper and easier to fabricate) for the Northern tier AND the mandated upgrades of all earlier guns. For the southern cluster, you had CH, H in Shield and JAO of Middletown CT to supply T2 and T3 sights for them, and also the upgrade program. Finally, Hemphill, which probably made the first adjustables of both types settled in to supply Winchester and the upgrade program. JAO did the same along with flip safties, but only later. IRCO did the same in the north, Inland and upgrades. I suspect as the early 1944 terminations approached and flip sight supplies dwindled for some, adjustables, Hemphill in the south and IRCO in the north, were diverted into production as needed. For this reason, I believe one must be very careful of declaring the LATE production carbine sights of the terminated makers upgrades. IF geographically it makes sense that they could indeed be OEM, then they need to be given the benefit of the doubt as to correctness. One needs to look past the guns themselves and attempt to get a feel for what was going on with wartime production.

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Originally Posted by USGI

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

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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.

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Originally Posted by BrianQ

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

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I only have the one, but it doesn't have the cut like the OP's IBM. - Bob

RPW: Timelines: most carbine makers were done, gone, finished by April 1944. That is the fourth month. Type 2 and 3 rear sights were just getting rolling about Feb-March of that year. Do you think that any of the other makers would be sending scarce adjustable sights to companies that were done a month later? NPM who never put anything but flip sights on their carbines sent IBM 20K assemblies in Feb 44. I have two carbines that came from the factory with type 2-3 rear sights, neither has any stake marks beyond the two used to secure the adjustable base, dead center in the dovetail. My NPM has a type 2 added in a rebuild it has both the punch marks and a very subdued chisel mark from the flip that used to be there.

I agree completely with you. Everything fits. I believe deliveries of most parts to the terminated wound down thru late winter early spring. They all knew in Jan Feb that it was over. So they ran their inventories down and purchased or swapped only what they needed to finish off what guns they could. Sights, if needed would, have come from local suppliers. IRCO north, Hemphill south. Hence the small numbers of these adjustables on the late terminated guns. We all assume that only the punch was used to secure adjustables. According to Ruth, IRCO and QHMC paired up to solve the problem of adjustables breaking loose. IMHO, I believe they initially used the same procedures to secure adjustables and flips. They didn't know any better. No new procedure would be recommended much less implemented until the problem manifested itself as more newer type sights were installed. I have an UN Quality from this time period with an IRCO T3 (geographically correct) sight. The staking is unlike any I've seen. 4 small punches very precisely and methodically placed in each quadrant of the dovetail. Almost as if they were testing to see what worked. Was it an IRCO/QHMC test gun? Who knows? Do I believe this adjustable sight is correct to the gun? Absolutely! Completely off topic. Watching news this morning. Saw footage of a French cop in Paris carrying what appeared to be an M1 Carbine!!! Oiler cutout, barrel and front sight unmistakable. Still going strong!

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Originally Posted by rpw7351

Saw footage of a French cop in Paris carrying what appeared to be an M1 Carbine!!! Oiler cutout, barrel and front sight unmistakable.

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Mini 14? Was it this...Reports: Paris Attackers Dead | NewsRadio KFBK

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Originally Posted by USGI

I only have the one, but it doesn't have the cut like the OP's IBM. - Bob

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Sorry, thought you were referring to the "I" cut under the front sight, which all IBM barrels have and is visible on some even though the front sight is installed properly. Some IBM barrels have an additional cut aft the "I" cut.

https://www.milsurps.com/images/impo...Barrels1-1.jpg