Peg, have you solved the magazine well alignment problem? If not, it might be necessary to get the frame to someone with the correct mandrel to form it back into shape.
If you chase out the threads, be sure to use the right tap. These are
English Whitworth threads. They have a different pitch angle (55 degrees) when compared with metric and SAE threads.
3/16" x 30 TPI Whitworth 55 degree threads
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Igitur si vis pacem, para bellum -
- Therefore if you want peace, prepare for war.