The transfer bar is what transmits the strike of the hammer to the firing pin, if it is gummed up or "out of tune" I think it could cause the same issue. It seems to happen a lot on the Sportsters and several have been sent back to H&R for "tuning".....the only other thing that I can think of is you're not fully pulling the trigger all the way to the rear as the trigger breaks, no follow thru with trigger pull can cause light strikes and inconsistent accuracy or at worst, failure to fire. I'd spray the heck out of it with cleaner if you don't want to tear it apart and pay attention to your trigger pull and see if that helps.