Yep, that’s why it may seem like I’m getting frustrated explaining to people that the hardware store is not an option. Checked it with a thread pitch gauge. a screw gauge, and the DRO on my lathe. it’s not uncommon for gunsmiths and gun manufactures to have proprietary screw threads and shapes and designs. Often the screw slots are indexed for decorative purposes so I’m gonna rebuild the screw one way or another.
Thanks for asking.