Thanks to all the above. I have considered all those options. I am shooting 150 gr psp and 180 gr sp and it happens to both. The damage is on the top of the bullet. It seems to hit the top edge of the chamber on entering and some of the lead on the top gets scraped and pushed to the rear of the top. It seems that the shells com up from the magazine at too steep an angle. The remaining shells in the magazine do not show any damage after firing and before chambering. Still looking for more suggestions to address this or there will be a 760 for sale soon.