I haven't had any issues with them that I could directly relate to the primer being defective. I had "one" that didn't ignite a month or so back, but when I pulled the bullet, and checked, the primer was intact and hadn't even broken up the compound. I figure since I was pushing to get the rounds loaded before heading out of town, I probably didn't seat it all the way. First time that has happened in years of loading.
Other than that, several K in rifle, and handgun have all gone off and shot great.
Mike / TX