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Semiauto Thompson Firing Pin Problems


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I had to replace my semiauto firing pin, ordered one from as it turned out, the Tommy Gun shop. It is properly installed, but the weapon will not fire now. It is cocked and I cannot get the frame off the receiver with the weapon cocked. Given that the Tommy Gun shop told me when my old bolt and firing pin supposedly screwed up, that they had to install this new and improved bolt that looks just like the one I had in it before, The firing pin they sent me should work.

 

Any ideas on how to get the receiver off the frame so I can trouble shoot it. I do not want to send it to the Tommy Gun shop again. Barring that, can anyone recommend someone else who can work on this thing?

 

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The semi auto firing pin is not a drop in replacement, it must me fitted to the gun. Even though it fits the bolt properly there is more material where it engages the sear, that is the area that must be ground to correct size. This is assuming you have the right pin, there were two types. PK of Diamond K can do this task, contact him for turnaround time and price.

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  • 4 weeks later...

Good advice from Deer Slayer, as usual, but, although a little late, I would recommend

getting the AIG Armorer's DVD on Tsmg/Semi-autos which covers putting all these

parts back together once you do that.

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  • 1 month later...

Hi

Just wondering if the Kahr 1927a1 firing pins will interchange with a 1980 manufacture West Hurley 27A5 that was made for the long Type 1 firing pin. My greatest concern that if the Kahr product is used,that any excess tolerance might crack the bolt face. Currently Numrich has only the Type 3 pin in stock and the tech claims both the Type 2 and 3 are compatible, however I am not certain if the so called "Type 1" pin is in reality the correct nomenclature for the long stem firing pin? In any case since having broken my firing pin, it has been nearly impossible to locate one of the identical types. I purchased one of the older "nub" type firing pins but they do not clear the firing pin channel. am curious of what to do, or a source for one of these firing pins. May have to ultimately try a precision machine shop to have one made. Thanks.

George

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Hi

Just wondering if the Kahr 1927a1 firing pins will interchange with a 1980 manufacture West Hurley 27A5 that was made for the long Type 1 firing pin. My greatest concern that if the Kahr product is used,that any excess tolerance might crack the bolt face. Currently Numrich has only the Type 3 pin in stock and the tech claims both the Type 2 and 3 are compatible, however I am not certain if the so called "Type 1" pin is in reality the correct nomenclature for the long stem firing pin? In any case since having broken my firing pin, it has been nearly impossible to locate one of the identical types. I purchased one of the older "nub" type firing pins but they do not clear the firing pin channel. am curious of what to do, or a source for one of these firing pins. May have to ultimately try a precision machine shop to have one made. Thanks.

George

They are the same internals not withstanding small deviations in manufacturing between Kahr/AO and West Hurley.

But before you do any replacements I would recommend doing a thorough study of the old and new parts before replacement

Just to make sure.

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Thanks so much T-Hound! Appreciate the response....Actually I have been doing that and found that the Kahr firing pin has much smoother finish overall compared to my broken WH pin which is quite rougher and far more crudely finished . My biggest fear is an action lockup by the sear on the new part, thus I am studying this quite carefully. Once again much obliged for the advice!!

George Layman

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Thanks so much T-Hound! Appreciate the response....Actually I have been doing that and found that the Kahr firing pin has much smoother finish overall compared to my broken WH pin which is quite rougher and far more crudely finished . My biggest fear is an action lockup by the sear on the new part, thus I am studying this quite carefully. Once again much obliged for the advice!!

George Layman

Also, you should note from the advice given in the 2nd comment by Motorcar, that if you

remove material from the bottom of the pin that catches the sear you will have

more than a lock-up problem. It could cause the sear not to catch and then you

get into an Olfsen/AR 15 situation where it might go partially full-auto for a burst. So

be careful what you remove from the bottom of the pin.

 

John/T Hound

Edited by T Hound
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  • 2 months later...

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