Check out http://www.perfectunion.com/vb/
and do a search for broken firing pin. Seems some Mini-30 owners were having issues with broken firing pins and were attributing it to steel cased berdan primed ammo. Seems the current theory is that it's due to the steel post under the berdan primer that's breaking the firing pin. Mini firing pins are pretty much a Ruger only item because they have to be fit to the bolt. Bear in mind that this is all speculation and to the best of my knowledge there is no way to prove the theory, but I'm not sure that I would risk it. I know there's a lot of people that feed their Minis nothing but steel cased berdan primed ammo that have never had a problem. By the way if you're like most Mini owners you've probably modified your Mini at some point so if it has to go back to the factory for a new firing pin (or any repair for that matter) Ruger will undo whatever mods you've made to the rifle and set it back to factory specs before returning it.