I had the issue with my J2Rxx. Nylon washer stopped or slowed progression of the peening until I finally got around to getting a new slide from Kel-Tec. No issues with the slide replacement. No issues with my JPMxx (though for non-related reason just now sports a new slide). I guess it is always possible for a CNC machine to be improperly set or maybe go out of tolerance and once again produce some bad slides. The batch would also have to slip by QC. I'm not a machinest, just guessing it could happen again.