The firing pin protrusion could be a tad short too, all mine are on the minimum side (ie, less than .050", one was closer to .040"). You can go to .060 a bit at a time, say .005" until you get reliable ignition. If you push the firing pin flush with the frame at the hammer contact (use a small screwdriver tip) you will see that it can protrude more than the hammer makes it go. You have to remove metal at the place in the frame where the hammer is being stopped. It does not take much filing!!! Your choice to relieve the hammer (easily replaced) or the frame.
My old guns really make deep indents in primers, especially the mil-surp rifles and old shotguns, compared to my H&R's. If the f-pin doesnt protrude far enough for a deep seated primer or a thin shell rim, it doesnt matter how hard the hammer/spring unit slaps the frame.