I have a Vollmer MP5 sear gun. I shoot both factory and my own reloads. For quite a long time it has been maintenance free. In the past two years I have had two firing pins that had their tip break off. As luck would have it, both occurred during a match - oh well.... I don't know if the pins were OEM. Any suggestions from the RKI's out there why this may be occurring and how to prevent it? Thanks