I have had this original Whitney-Kennedy rifle chambered in 44-40 for a couple years. Today I went out and shot it for the first time.
Bullets are soft, .429, 200 gr from a Lee mold, lubed with mutton tallow-beeswax. They are loaded over 40 gr compressed FFFg Goex with a thin cardboard wad in new Starline cases. Winchester large pistol primers.
I got successful shots off about 25 %. Same rounds went off 100% in my new Winchester Miroku m1866.
The hammer seems floppy and I suspect the mainspring is weaken or needs to have a tension screw adjusted... In fact there is a possibility when I did a complete takedown and cleaning months ago that I did not fully tension it... I've taken down so many of my lever guns, honestly I don't recall. On a fired cartridge, I saw there was a nice primer strike and the primer was backed out a LOT.
So I am wondering if a weak or under -tensioned spring would allow the primer to back out, or would there have to be an additional factor causing excessive headspace?
It also seems that the firing pin does not retract fully after chambering a round and there is no spring tension in THAT mechanism.