1928a1 Savage smooth bbl mark - large "O"??

[Lewisfan]

I have a late Savage 1928a1 with the barrel markings as shown below. I've tried searching posts / books for this mark but only find references to small "o" marks next to index lines that were not aligned with index marks on the receiver. The barrel does have the top center punch marks with the "P" proof mark.  A second index line on the barrel does align with the receiver index line.  It is a Savage marked barrel.  The gun is a S-486XXX serial number.  

Any significance / explanation for the (?) large "O" mark?  Could this have been done with the original barrel installation?   Or is this likely re-barreled?  The gun's finish looks original (still has swirls from the machining).

[TD.]

Look at the compensator pin on both sides. Are both ends of the pin nice and round? Or is one or both ends flattened?  

[Lewisfan]

Don't seem flattened to me but pics attached since I'm a newbie...

[Bridgeport28A1]

It looks like a nice Savage plain barrel that is indexed and has a firing proof punch. 

I am assuming your Thompson has a plain L rear sight. 
 

[Lewisfan]

Yes. Plain L rear sight. 

The big "O" mark is mostly obscured under the forearm. The pic showing this stamp is taken with the forearm removed. Is that a firing proof mark?  I thought the "P" at top center of the barrel was the firing proof?  Not arguing, just trying to learn...

[Bridgeport28A1]

The punch inside the loop of the P at top center is the proof firing punch.

The punch in that location is consistent with Savage production. 

 

[TD.]

Lewisfan,

Great pictures! And a great question. I too have wondered about the significance of these "O" or oval circles found on Thompson barrels. I have always thought barrels marked in this manner were replacement barrels. My thoughts only - others on the Thompson forum are much more knowledgeable on the military Thompson guns.  One thing I noticed about the compensator on your Thompson is how the metal around the compensator pin is peened over (see picture below) on the right side by the compensator pin. It does not look like a clean install to me, but I may be way too picky viewing a late Savage Thompson. However, replacement barrels on military Thompson guns are commonplace and do not really impact value or desirability if the correct replacement barrel was installed. Original finish and matching frame and receiver are much more important. It appears you have a nice late Savage Thompson submachine gun. I look forward to what other forum members have to say.  

 

[reconbob]

   Hello - all original Thompson spare barrels were proof fired- hence the P. When a spare barrel was fitted to a gun and proof fired it was center punched inside the P and at the front of the receiver.

    Many barrels have a small O stamped at the rear in addition to the S. I do not know what the small O means. The large O in your picture, I do not know what that means either, and the two draw lines - who knows? But we would expect to see only one draw line.

  I agree that the raised edges around the hole for the comp pin are a clear sign the pin has been removed and refitted 

Bob

[DZelenka]

May very well be an original barrel based upon the direction of the P. Replacement barrels that I have seen have the P readable from the muzzle end, not the receiver.