Unknown M1 Carbine marking

[scoutjoe]

IMG_20230611_163918978.jpg

Alright I'm sending this one out to the collective brain trust as my Google-Fu is failing me. This is on a M1 carbine barrel directly above the chamber which is marked Underwood 8-43. This was likely an Italian return gun that came through the CMP. I was using the J.C. Harrison book "Collecting the M1 Carbine III" to put together a handful of carbines that a collector tore apart and I pieced back together. I couldn't find any reference of "GM" for the subcontractor mark.

I could only find a reference to "Sometimes the proof mark may be found on top of barrel above the chamber. Not to be confused with marks other than a P sometimes found in this location. Other marks in this location were used internally by companies with meanings known only to that company. "
from http://www.uscarbinecal30.com/barrels.html

Any guesses?

[GOYABEAN]

Volume is very low but he mentions GM marked on one of his M1 carbine

[Delkal]

The Italians put their rebuild markings there so I do not think it is USGI. Normally the stamp has FAT in it but anything goes during a rebuild. Id the stock FAT marked?

Does the barrel have any other US markings on top near the muzzle? If it does this is just a rebuild stamp. If the barrel has no other markings it is probably a replacement.

[scoutjoe]

The Italians put their rebuild markings there so I do not think it is USGI. Normally the stamp has FAT in it but anything goes during a rebuild. Id the stock FAT marked?

Does the barrel have any other US markings on top near the muzzle? If it does this is just a rebuild stamp.

The barrel is a Underwood marked barrel 8-43 with flaming bomb. Many of the carbines had FAT markings on the stocks and some had markings above the chamber like this one.

[scoutjoe]

Volume is very low but he mentions GM marked on one of his M1 carbine

Ya that's an Inland marked barrel in the video. While Inland was a division of General Motors it's treated as its own manufacturer. Similar to the Saginaw Gear or Saginaw' Gear' were both divisions of General Motors but are treated like two separate divisions.

[Delkal]

Underwood made their own barrels so the "GM" proof was not to signify the subcontractor who made the barrel. Companies were known to swap barrels but the barrels already had the original makers markings on them so they would be an obvious mismatch to the receiver. If the barrel and receiver of your rifle are both marked Underwood it is likely it is the original barreled action both made at the factory. Your link mentions some manufacturer marks were sometimes placed there for unknown reasons but this is also where the Italians placed a rebuild stamp so this is a mystery.


I would post this on the CMP forums. in the Carbine section. They have a lot of people who know stuff like this.

[ScotsGuards]

I've been studying and collecting M-1 carbines for years and have never seen that marking on any. Including those made by General Motors companies. Let me ask a few people if they've ever seen that mark.

[McSull]

Sure it's not a W9?

[scoutjoe]

Sure it's not a W9?

With all the different markings out there, then the likely markings made by other countries I'm not sure of really anything

The "W#" markings were usually something Winchester did. While Winchester could of marked an Underwood barrel, why would they? Winchester made their own barrels or sub-contracted out to Buffalo Arms.

[JenniferG]

Italian marking Giuseppe Marinara. He owned the restaurant down the road from the factory