Stick magazines and the Thompson, West Hurley vs Worcester.

[HKUriah]

I've got 2 Thompsons.

A 1927 made in West Hurley and an M1 made in Worcester.  (Both are moden made semi-autos)

Both are nice guns, and I can see no real difference in quality.

The 1927 came with a 38 round drum, and 3 30 round sticks.

The M1 came with 1 30, 4 20's, and 2 10 round sticks.

The drum of course is 1927 only, but what is interesting is how the sticks that came with the 1927 will fit and function in the M1, but the sticks that came with the M1 will not fit on the 1927.

I have seen this mentioned before in other threads in passing, but I wanted to start a converstion specifically about this topic.

Quick examination revealed that there are differences between the sticks that came with both guns.   The 1927 sticks have a sort of oblongish hole in them near the top, but the M1 sticks had a perfectly round one.  Also, just above this hole, there is a small piece of metal that is is a slightly different position on the two sets, and is noticably longer on one group than the other.  Finally, the width of the, I'm not sure what it's called, the part of the magazine that slides up a slot on the rifle, is ever so slightly wider on the M1 mags than the 1927's.

There are also differences on the guns.

The aforementioned slot on the M1 is clearly bigger than the 1927, and is more oval shaped, while the 1927 slot is a little smaller and trapezoid shaped.

All of which begs the question...   Which of these designs is "true" to the orginal design, and which is a modification?  Or, if you happen to find any GI surplus sticks, will they fit both guns, or just the Worcester made guns?   I am assuming that these differences are caused by the difference between where the guns were made, and not the model that they happen to be.  (Which of course makes me want to handle a West Hurley M1 and a Worcester 1927 just for comparison purposes.)

Anyone have any answers to these questions?  

Or care to comment on the phenomenon?

I have seen comments about how it is possible to modify the magazines or the guns, but since I have some that'll work in each, I'm not gonna do anything about that, but it is a curious quirk of the reality that is the Thompson.

To me anyway...

[HKUriah]

And before anybody asks, here are some pics.


West Hurley 1927
http://i1135.photobucket.com/albums/m625/HKUriah/TommygunWestHurley1927_zpsbb4bf9e1.jpg

Worcester M1
http://i1135.photobucket.com/albums/m625/HKUriah/TommygunWorcesterM1_zpsf20e6adb.jpg

Magazine Slots
West Hurley 1927 on left   Worcester M1 on right
http://i1135.photobucket.com/albums/m625/HKUriah/TommygunMagazineSlots_zps3b5ea91c.jpg
Note how the right one is rounded and slightly bigger


Magazines
West Hurley 1927 on left  Worcester M1 on right
You can clearly see the differences.  The hole is just the most obvious one.
http://i1135.photobucket.com/albums/m625/HKUriah/TommygunMagazines_zps7f1b6a3e.jpg

[DeaconKC]

The round hole is the original shape for the hole you mention. The oblong shape is cut into them to fit current production guns that have a slightly different magazine catch.

[HKUriah]

The round hole is the original shape for the hole you mention. The oblong shape is cut into them to fit current production guns that have a slightly different magazine catch.

Okay, I have to admit that this confuses the heck out of me.  If the oblong shape is newer, and to fit in the newer guns, that means that my Worcester made M1 is OLDER than my West Hurley 1927, because the original round style holes do not fit in that gun.

But I thought the West Hurley era was in the past, and current production was in Worcester.

My brain hurts...

[Border Ruffian]

Okay, I have to admit that this confuses the heck out of me.  If the oblong shape is newer, and to fit in the newer guns, that means that my Worcester made M1 is OLDER than my West Hurley 1927, because the original round style holes do not fit in that gun.

But I thought the West Hurley era was in the past, and current production was in Worcester.

My brain hurts...

HK, I have essentially the same set of guns.
There are a couple of possibilities: 
1. slight dinensional differences in the mag catch, this means fit the mag to both rifles, it how I do my 30 rounders, I don't use the 20s with my TM1.
2. modification to the magcatch, this is popular becaues original mags don't have to be modified.

You may just have to tweak them some.

[Sacramento Johnson]

Howdy!
I have handled original WW2 era 30 round magazines made by the Crosby Company and the Seymour Company. They came into use around '42 and were meant to replace the 50 round drum (which the M1 did not take). They all had round holes.  They were to be used with both the '28 model and the M1.
The receiver cut out for the magazine was rectangular on the '28.  
I remember hearing something about the round hole vs the oval one on the magazines, but can't recall the details now.
I think it had something to do with a specific modern semi-auto reproduction.  (Maybe when Kahr was making them?)
Do you all see any '28s at your matches (in states that allow them)?