Short quiz: two Thompson barrels

[RCS]

Short quiz, photos two two Thompson SMG barrels - why are they different ?

Information

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[browningautorifle]

Is one from a 1921 and one a 1928? Early '21 Guns have thinner fins than later ones. Fins on a Colt Gun are more rounded than WW2 Fins. WW2 1928 Fins are more square. some WH barrels have rounded fins...

[Woodsy]

As above. The '21 barrel is also serial numbered while the WW2 production barrels were not. The WW2 barrel is probably Savage manufacture.

[RCS]

You guys know your Thompson SMG's

Thin fins were Colt Model 1921 TSMG, rear of barrel breech numbered 1 to 999 to match serial number, only
three digit numbers nothing higher. Thick fins were 1928A1

The 1928A1 had different contractors Savage/Stevens, Auto Ord

[browningautorifle]

Well, I cheated. I had an earlyish 1928 with many early features. It had a Nickle bolt, and one piece ejector for instance. It was marked to the Bapty Movie Company...a vet bringback from Italy was numbered S68038. Although a Savage gun, a very elderly collector from Chicago/Portland told me it was made on the Colt machines. I've examined lots of them.

[Woodsy]

I have owned about 8 TSMG's including 2 ex-IRA '21's, and worked on a good few as well. I only have a tidy M1 Thompson now.

[RCS]

Jim, I remember photos of your Savage, stock bolts not factory but does not matter.

Here are photos of a Savage bolt that came from a British proofed BNP Savage Model 1928A1,
when I saw the bolt, I traded the owner another bolt.

They use to call these modified bolts " the paratroop bolt"

[browningautorifle]

stock bolts not factory

I forgot about those...I had to add those after the fact. There had been some in there at one time to help remedy a split stock but they had been removed. The whole stock came a part like a clamshell and had to be redone. There had been pins and they had been unscrewed too. The stock had the anchor marking so it had to stay. I found a pair of heavy wood screws from a C6 butt, (Mag58) and they fit perfect so they stayed. That gun is now in a dewat collection in Quebec. Sad but true...

the paratroop bolt

Yes, so the weapon could be placed on safe when bolt was forward. The actuator could easily catch in equipment and since it too was advance primer ignition would fire when a cartridge chambered...

[RCS]

By 1923 a special Thompson smg was developed with a longer barrel chambering a special experimental cartridge based on the 45 ACP cartridge case. The new 1923 cartridge used a case one inch long with a 250 gr jacketed bullet at 1450 fps. Both REM-UMC and Winchester loaded this cartridge. Without any interest from law enforcement and military, this soon died,
these 1923 cartridges still turn-up, headstamped REM-UMC 45 ACP.

my photo shows a 9,8 Colt, 45 Thompson 1923 and 455 auto

[browningautorifle]

I have a couple .455 and lots of variation of .45ACP but never found an M1923 cartridge. Closest I have is the .45 Win Mag...about a quarter inch longer.