Some bolts require the extractor to be riveted to the bolt nose.
Truing the action includes truing the bolt face. If the extractor has been riveted in place, we can either pop off the rivet and true the bolt face the way we do for non-riveted extractors or we can use a tool to cut the surfaces under the extractor. When possible we’d rather avoid removing the rivet so we don’t have to re-install a new rivet after we’ve trued the bolt. Re-installing a new rivet gives opportunity to damage the bolt. So, we opt to cut the bolt face under the rivet without removing that extractor.
There are some cutters made specifically for this task. However, we preferred to make our own “purpose built” tool to our specs and tolerances.
When we’re all said and done, we’ve got a perfectly trued bolt face and we didn’t have to remove the riveted extractor. 🙂