Original mags

[Larryp44]

I have to semi auto thompsons M1A1 and 1927 A1…. I also have some original 20rd mags. I noticed that my semi auto guns require the mag catch hole be oval but all my original mags are round. Instead of drilling my original mags, can I replace or modify the mag catches…???

[68coupe]

Absolutely! It's the preferred method by many. You'll need to remove approximately 0.1", the same amount you would have to modify the hole in the mag. However, once you modify the mag catch, the Kahr/WH mags that you have, which currently fit, will no longer fit. My recommendation is that you remove metal from the mag catch a little bit at a time. It'll be a time consuming process to check fit between sessions of metal work. Once material has been removed, it's a real pain to TIG weld to replace it. Be sure maintain the positive angle of retention on the mag catch, as it's vocabulary building, at best, when the mag drops accidentally before it's empty. I opted to modify the mags instead. I can't afford a "real" Thompson, so the mags will stay with my guns forever. I have a Kahr and a WH. The WH is a Korean conflict commemorative, all blinged-out with gold bits and decorative pieces throughout. When I got it, I thought it was too pretty to shoot. Not any more. The two are equally fun to shoot and perform cleaning & maintenance.

YMMV, Karl, 68coupe

[Larryp44]

Thanks…

[peter kohler]

i have three thompsons that i modified the mag catch on     best thing to do     you can also get the semi mags welded back up to work like the originals      ive done a bunch of them    

[pstidan]

37 minutes ago, peter kohler said:

i have three thompsons that i modified the mag catch on     best thing to do     you can also get the semi mags welded back up to work like the originals      ive done a bunch of them    

Please post some pictures.