Despite removing as much friction as possible, when I ran the heaviest Wolff reduced power hammer spring the gun would not make it though a full cylinder. I was running 45 Colt primed with Remington, Winchester, and CCI. None of them made six consecutive single action shots. Double action was understandably worse.
I own a GP100 and I have wondered if the failure to fire might be related to the transfer bar not striking the frame flush and being torqued slightly by the hammer. By design the transfer has a lot of play. If this play causes it to sit off the frame, even a few thousands, could it bleed off the energy of a hammer strike. The last time I had the transfer bar out of mine I noticed a very light dimple on the face (looks like the firing pin mark). A little Prussian blue and a good stone should take care of squaring up the face in short order. And if the firing pin channel has soot lodged in the spring or around the pin this might cause FTF just like my old 1911.
Your thoughts here?