Never had, nor even seen, a dud primer in a handload with the exception of some that were contaminated with oil, like Bronco22000 said! Oil or grease MUST NEVER be on your fingers or any other place when you are handling primers!!

In Alaska once, a kidI knew came over and used my reloading equipment to load up some .308 ammo for his upcoming bear hunt. He returned,relating a sadtale of "duds-bad primers", and swore never to use another reload!!! Turned out that he had omitted putting POWDER in about 1/3 of his cases. Bullet bases were black as hell, primers had worked perfectly! (He was lucky he didn't get a bullet stuck in his bore, since he did get a shot at a bear. He got it with one of his bad reloads! One he'd put powder in, no doubt!!)