Ok, I realize this is quite some necroposting, but the issue still comes up, so here something for those who come to this post in search of answers.
I don't have all of them, I'm still testing, but I have some, and some information that perhaps my help others.
I've been fightinh this issue for quite some time, I've made dozens of tests, and I've found out several things, managing to fix the issue in my Navy and Walker, but not in my 1849 Pocket. So, here what I've found.
Cap jams happen
1) in the best case scenario when the cap prevents the cylinder to turn, then in the next worse
2) when it comes to be stuck between the frame shield back curve and the hammer, preventing the hammer to hit the primer in the next chamber, and then, worst scenario,
3) when a cap or piece of cap falls down in the mechanism and locks up everything for good.
Now, the quick fix for 1) is helping the cylinder back and forth until the cap fragments are expelled from bewteen cylinder and frame, for 2) removing the cap with the tip of a toothpick or something like that and for 3), well... you have to take down the whole damn thing.
But what everyone wants to know is how to prevent the damn caps to cause issues at all in the first place.
To this end, I've read a lot of things, some work, some not, like flicking the gun while cocking the hammer, filing or filling the safety notch on the hammer, or using different nipples and such. Some seem to work for some, but not others.
For example, I rounded up the corners of the safety notch in my Uberti 1851 Navy, and that solved the issue.
With "solved" I mean I've shot something like 36 cylinders without a single cap jam.
I did the same in my Uberti 1849 Pocket, and it didn't do any difference at all.
Why?
Well, for starters, let's remember original Colt revolvers worked. They were considered very reliable, and dependable. Cap jams existed but were rare. Yes, they were a flaw in the gun, as Remingtons apparently never had them, but they were not that common anyway, or nobody would have carried a Colt, if it jammed every other shot.
Therefore, it must be something in how the gun or the caps are made.
So, the next interesting question is "how the cap jam happens?"
After some tests I've found basically three ways they can happen.
A) Fragments of the cap badly blown gets stuck between cylinder face and recoil shield. This usually causes type 1) cap jams.
That's what the slot in the recoil shield it's meant for: to leave room for cap fragments to slip through and get out of the action. This can be quickly filled in crud, particularly if shooting dirty powder. Also, it depends upon how modern caps are made: they are far thicker than a few vintage caps I could observe, who looked like they were made more like copper foil than stamped copper sheet: being far thinner they almost disintegrated. I couldn't handle them and press them between fingers to ascertain how thick and hard they were, but they sure looked flimsier than our modern caps. Unfortunately we must live and shoot with what we have, but choosing softer, flimsier caps may help, as well as keeping the gun very well oiled with black powder suitable oils, and using nipples that leak as little blowback as possible.
B) The blown cap gets stuck in the safety notch in the hammer, pulled back and falls in the gap between receiver and hammer. You can detect this kind of cause by shooting a shot, then cocking the hammer while carefully looking in bright light at the hammer's face and nipple: you will see the cap being pulled back and falling. This causes type 2) and 3) jams. Smoothing the notch corners will cure this issue 100% or as close as 100% as you can get.
C) Blowback from the nipple will blow the cap against the hammer, and the hammer back enough to allow the cap to fall between hammer and frame. This causes typically a type 2) cap jam, very rarely type 3). You can detect this kind of cause by cocking the hammer while carefully looking at the nipple and hammer face, and you won't see a cap there, because it's already been blown back into the frame. You'l find it there, already sqashed by the hammer, pushed by the mainspring.
This is tricky, and is what is happening in my Colt 1849 Pocket.
The causes are deemed to be
- nipples with large flash hole causing undue blowback against the hammer
- weak hammer spring that lets the hammer easily be blown back, also considering the Pocket hammer is much lighter than the Navy's so, less inertia.
Only, mine is a late model, so yes, it already has nipples the same size as the Navy (they are interchangeable, not historically accurate but very practical) and yes, it already has nipples with a small flash hole. I don't know if it's as small as, say, the Slixshot nipples, as I don't have them.
And, finally, it should have the strongest mainspring.
But it does it all the same.
What to do? I tried to round the safety slot corners, to no avail.
I tried to cut a small notch in the nipple crown as suggested by some, as it was meant to help the cap blow upwards instead of back into the gun, to no avail.
Next steps are
- getting another mainspring to try the double mainspring trick that should make the hammer harder to blow back
- getting Slixshot nipples. This is not easy, as I will have to get them sent to Italy. Mumble mumble... As an alternative, I will try to drill a hole on the side of the nipples I have, like the one Slixshot have, that is supposed to help destroy the cap and help divert much of the blowback laterally.
PS: yes, I know of the cap rake (pin fitted into the frame to prevent the cap to come back) but I don't like it and the gun should work well without one.
I'll keep you posted.
