I tend to stick with ammo that comes with sealed primers, and am very careful to keep the breech face and chamber dry after cleaning. Never had a problem. That said I may have to adopt some schedule for carry ammo replacement. I also test fire a sample from every lot number before I accept for carry. During past ammo runs quality fell, and lot number tests identified a bad lot that was replaced by the manufacturer. Basically I shoot a box of 50 from a lot in a specific pistol and call it good.