Barrel Threads on Current Production Thompsons

[jojeep]

I have thought about purchasing a Newer Semi Auto Thompson, I have two older ones(M1&27).

I know AO using Press Fitted Cutts Compensators, but did they change the Threads at the Receiver End ??

They have always been what is know as Straight Cut Threads.

The reason I ask is I took a 27 built in the 1970's and put a 14.5 Green Mountain Barrel on it,about 10 years ago and thought about building another if I purchased a New Production or a use one built in the last few years.

If anyone has recently changed or pulled a Newer Semi Auto Barrel, I would like to know.

Thanks

Edited March 8, 2019 by jojeep

[06AngusSG]

Mine is from 2011 and I put a green mt on it but I've seen threads pass by in here suggesting that the threads have indeed changed sometime in the past few years.

[Broadarrowmaint]

I took off my 16.5 barrel on my newer Kahr Arms 27 and Installed a blank only barrel that has identical threading to a usgi barrel(it was one of Philadelphia ordnances blank barrels) and the philly barrel needing to be slightly modified to fit right. So to answer your question, yes the newer barrels on the newer 27s have slightly changed the threading at the receiver end.

[lamellarllc]

I have a current production "commando: model and bought a green mountain M1 barrel , i hope the threads are right, what mods was needed for the barrel to fit into the current receivers, Khar did tell me that the thread pitch was the same as the originals

[Broadarrowmaint]

All that was done to mine to make the barrel fit the new production Kahr receiver was a square file and barely sanding down the threads. Before I did that I tried to screw on the barrel to the receiver and it was about 1/8 of an inch from being fully seated and it would not thread on anymore. A little filing and it went right on

[jojeep]

Thanks everyone for the Information.

If you have to File the top thread to Modify then it is not a Straight Cut Thread, which would indicate that the "Valley" of the Thread is

a "V" rather then a Squared flat bottom "U".

This V shaped Barrel Thread is more like Standard Pipe Threads one might see at a Hardware Store.

If I decide to purchase another 1927 to put a Green Mountain Barrel, it would be best to look for an Older West Hurley/Pre-Kahr.

[jojeep]

Changing to a Standard Pipe Threads probably saved Kahr alot of Time and Money in Machining. Edited March 10, 2019 by jojeep