I finally got to the range. I was able to see if my fixes worked and they did. The gun went from not being able to shoot a full mag trouble free to running mag after mag reliably. Polishing the chamber fixed the sticking cases. Polishing the feed ramp fixed the FTF. The most important was filing the the extractor claw. It came from the factory with not enough room to grasp the rim of the cartridge. The gun now works with various ammo including Remington subsonic. This was a surprise. This gun will be going to the range on every trip. As long as no one notices that it’s pink.