My cap gun is VERY reliable. I cannot remember ever having it miss-fire. My flinters not so much- BUT- they ALWAYS go off perfectly at least the first 10 times when on a trail. Then, one gets a bit distracted, doesn't notice the flint has a hard round spot going to hit the frizzen and cause a miss fire, or a piece of fouling off the frizzen or pan blocking the vent - there are a number of things can cause misfires or flashes in the pan.
However- the first 10 shots or so, never a misfire, with either & never when hunting with them.