If you have a good strong spring, the safety off, a clean dry bore, a good nipple with a clear flash hole, good dry powder and good magnum strength primers you will have zero misfires with that rifle. That's all there is to it. From what you describe I would guess your problem is either in your nipple or your primers.
That secondary safety should be turned all the way out. I personally do not use it when I am in my stand.