How old is the brass? That top case looks like it has a crack starting on the tapered portion.
How close to max is the load you're using? If its a bit warm, the cases could be sticking a bit to the chamber, making the extractor work extra hard, and causing a bit of deformity to the rim in the process.
The gouge on the tapered portion could be a long extractor... remove the slide, ease a case under the extractor and see if the "nose" of the extractor is touching the tapered portion of the case in front of the rim. If it is, you may want to stone off a few thousandths on the nose of the extractor to prevent contact.
How close to max is the load you're using? If its a bit warm, the cases could be sticking a bit to the chamber, making the extractor work extra hard, and causing a bit of deformity to the rim in the process.
The gouge on the tapered portion could be a long extractor... remove the slide, ease a case under the extractor and see if the "nose" of the extractor is touching the tapered portion of the case in front of the rim. If it is, you may want to stone off a few thousandths on the nose of the extractor to prevent contact.
