USGI Thompson magazine question

[Flammenwerfer]

Anyone ever mod the USGI thompson magazines for use in the semi auto AO versions? From what I understand you just have to expand the hole for the magazine catch. I'm mainly wondering about the way to go about it either A.) use a Dremel tool or B.) use a drill press

I just got my lightweight Thompson and to keep things economical I'd like to use the surplus mags since they are plentiful and close to 1/3 of the price of the AO magazines.

Thoughts?

 

[Hayata]

I used a dremel on mine with a rotary stone. You have to go SLOW. Grind, test fit. Grind, test fit.

Or I think there's a way to modify the latch to use the GI mags but I didn't want to modify the gun.

The drum is the way to go. Needs a tripod, though. Or I need to go to the gym...

 

[Flammenwerfer]

I thought about changing the mag catch as well, but I figured the surplus mags are cheap enough to fool with. I'll give the rotary stone a shot this evening.

 

[97 winchester]

Drill press ,vise and end mill works for me. CNC mill worked even better . lol.

 

[shogun3]

I used a mill to modify mine. I made a temporary jig to get alignment correct.