Thompson mag
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Jerod, yes.
GI mags have to be modified. Simple mod. I did mine with a demel tool. Takes only a few miniutes.
The hole in the rear of the mag has to be "elongated"- lengthened slightly at the bottom.
If you put a GI mag in your gun, you will see what needs to be done to make the mag mate to the gun.
Remove metal bit by bit til mag "clicks" in place.
GI mags have to be modified. Simple mod. I did mine with a demel tool. Takes only a few miniutes.
The hole in the rear of the mag has to be "elongated"- lengthened slightly at the bottom.
If you put a GI mag in your gun, you will see what needs to be done to make the mag mate to the gun.
Remove metal bit by bit til mag "clicks" in place.
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Modififcation Instructions for Thompson Magazine
Click here for instructions to modify GI Thompson magazines: http://www.auto-ordnance.com/fittingt11.html
We have brand new, original US GI WWII Thompson 30 round magazines. High gloss blued: http://www.bmgparts.com/other.html
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BMG Parts Co. 775/671-7500
Click here for instructions to modify GI Thompson magazines: http://www.auto-ordnance.com/fittingt11.html
We have brand new, original US GI WWII Thompson 30 round magazines. High gloss blued: http://www.bmgparts.com/other.html
BMG Parts Co. 775/671-7500
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550 Posts
I heard you can just modify the mag catch in the gun too, leaving the original mags intact, and just order another mag catch if you want a spare around. Thats what I would do. Modify 1 part on the gun rather than a bunch of original mags...
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that sounds like 100 times better but i have yet to hear anyone offer that idea!
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Mag Catch
I have done lots of TSMG mags for friends over the years. The problem is this, they are gun-specific. On the last one I did, I wanted to change the catch insted of the mags(less work) but found out the catch nubbin would be all but gone after lowering it. Modifying the mags is a pain but there are gazillions of them. They are as common or more common than Sten mags and I don't know why they are thirty dollars, they just are. F
I have done lots of TSMG mags for friends over the years. The problem is this, they are gun-specific. On the last one I did, I wanted to change the catch insted of the mags(less work) but found out the catch nubbin would be all but gone after lowering it. Modifying the mags is a pain but there are gazillions of them. They are as common or more common than Sten mags and I don't know why they are thirty dollars, they just are. F
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11 Posts
Here's the mod from http://www.1927a1.com/
1927 Semi-Auto Magazine Catch Modification
The semi automatic Thompsons will not accept original G.I. 20 and 30 round stick magazines.
The magazine catch must be modified by lowering the lip that engages the magazine .100" while maintaining the original contours and shape.
This is commonly achieved with a Dremel tool or files.
Make certain that the firearm is unloaded, place the safety in the fire position and squeeze the trigger.
Using a dowel or other object that will not mar the finish of the frame push up on the pivot plate finger that holds the safety leaver, push the safety out.
After you have removed the safety, move the pivot plate so the ends of the pins are flush with the side of the trigger frame.
Pivot the magazine catch out far enough to clear the magazine engaging protrusion from the hole in the trigger guard.
Push on the pin part of the mag catch on the far side while pulling the catch out of the hole.
Once the magazine engaging protrusion has cleared the side of the trigger guard, carefully allow the catch to rotate and unwind the spring.
Remove the catch from the trigger housing . (Assemble in reverse.)
When re shaping the magazine catch, you must duplicate all the contours and angles when lowering the engaging surface.
Removing .100" will allow use of unmodified GI magazines.
Be careful not to remove too much metal.
You may have to re fit and test several times to achieve the optimal shape.
1927 Semi-Auto Magazine Catch Modification
The semi automatic Thompsons will not accept original G.I. 20 and 30 round stick magazines.
The magazine catch must be modified by lowering the lip that engages the magazine .100" while maintaining the original contours and shape.
This is commonly achieved with a Dremel tool or files.
Make certain that the firearm is unloaded, place the safety in the fire position and squeeze the trigger.
Using a dowel or other object that will not mar the finish of the frame push up on the pivot plate finger that holds the safety leaver, push the safety out.
After you have removed the safety, move the pivot plate so the ends of the pins are flush with the side of the trigger frame.
Pivot the magazine catch out far enough to clear the magazine engaging protrusion from the hole in the trigger guard.
Push on the pin part of the mag catch on the far side while pulling the catch out of the hole.
Once the magazine engaging protrusion has cleared the side of the trigger guard, carefully allow the catch to rotate and unwind the spring.
Remove the catch from the trigger housing . (Assemble in reverse.)
When re shaping the magazine catch, you must duplicate all the contours and angles when lowering the engaging surface.
Removing .100" will allow use of unmodified GI magazines.
Be careful not to remove too much metal.
You may have to re fit and test several times to achieve the optimal shape.
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550 Posts
Mags aren't SO cheap anymore........
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697 Posts
Jerod I have 7 mags that have been modified for an auto ordnance M1 Thompson. I'll swap you for 7 unmodified. You pay shipping your way and I'll pay mine. P.M. if interested. Or anyone else for that matter. Chris
I finally swapped out the mag catch
Took the Khar mag catch off and put an original USGI made one on. Guess what? No difference. The position of the mag catch axis is the issue. Both parts side by sude (new and original), are identical. Eventually I will modify one of the mag catches with the dremel.
Took the Khar mag catch off and put an original USGI made one on. Guess what? No difference. The position of the mag catch axis is the issue. Both parts side by sude (new and original), are identical. Eventually I will modify one of the mag catches with the dremel.
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