Howdy
I have two Remmies with R&D cylinders in them, and I had a very similar problem with one of them.
I don't think it has anything to do with the trigger. It is because the bolt is not resetting when the hammer goes all the way forward. Just like a SAA, the bolt of the Remmie is split, with two legs. the bolt is actually made of spring steel, because one of the legs has to flex. There is a wedged shaped piece built onto the hammer. It is down near the bottom of the hammer, on the left side. (Working from memory here) This part of the hammer is called the Cam. It is disk shaped, with a slanted surface. In other words, the top of the cam has a rounded surface, but the face of the cam angles toward the hammer and blends back into the hammer at the bottom.
The way a Colt or Remmie works is when the the hammer is pulled back, the portion of the hammer where the cam is located rotates up. This causes the rounded surface at the top of the cam to engage the hook on the right side of the bolt. As the hammer continues to rotate back, the rounded surface at the top of the cam keeps pushing the rear of the bolt up. That causes the bolt to pivot around its screw, lowering the business end of the bolt and withdrawing it so the cylinder is free to turn. As the cam keeps rising, eventually the hook at the rear of the bolt slips off the cam, and the bolt spring pops the bolt back up. The bolt spring causes the bolt to bear against the cylinder, and when one of the locking slots appears, the spring pops the bolt into the slot. That locks the cylinder in position.
The other half of the cycle is when the hammer is lowered. When the hammer is lowered, either by firing the gun or gently lowering the hammer, the wedge shaped portion of the cam pushes the flexible leg of the bot to the side. With the flexible leg shoved to the side, the bolt spring maintains tension on the bolt and keeps it in the upper 'locked' position.
With me so far?
To complete the cycle, the flexible leg of the bolt must pop back to its straightened position, with the hook repositioned over the top of the cam, so the cycle can be repeated.
I'm pretty sure that is the problem with your Remmie, the bolt leg is not popping back over to the side, it is remaining in the shoved over position, so that when you try to pull the hammer back, the rounded surface at the top of the cam is not engaging the hook at the rear of the bolt leg. The bolt spring is keeping the bolt in the up position, not allowing the cylinder to turn.
I had the exact same problem with an old EuroArms Remmie that I put a R&D cylinder into. The hammer has to be able to move forward enough for the cam to rotate down far enough for the bolt to reset, allowing the spring leg to pop back over the top of the cam. It turns out, the firing pins on the conversion cylinder are just a tad longer than the nipples in a C&B cylinder. So even though the gun worked fine with the C&B cylinder, with my Remmie the slightly longer firing pins were preventing the hammer from falling far enough forward for the bolt to reset on top of the cam.
Try this test. Put the original C&B cylinder into the gun and cock the hammer. Then gently lower it. Listen very carefully. Just as the hammer gets almost all the way down, you should hear a soft click as the bolt resets. Then try the same test with the conversion cylinder. I'll bet you won't hear that soft click. If you don't hear the same click you heard with the C&B cylinder in place, your bolt is not resetting.
There are several ways to approach this problem. I do not recommend messing with the bolt leg. You could mess up the timing. I suppose one could grind down each of the firing pins a bit, so that the hammer could fall down a little bit farther, where it needs to go for the bolt to reset.
What I did was very carefully remove just enough metal at the top of the cam so that when the hammer goes forward to the new position, the bolt can clear it and the leg can pop back over to the side. This is not a job for a Dremel tool! I used a jewelers file to very carefully remove just a bit of metal from the top of the cam. I did not file it flat, I was careful to maintain a curved surface. This involved taking the gun apart, removing a bit of metal, then putting it back together again to see if I had removed enough metal. I don't remember how many times I took it apart and put it back together again until I got the result I was looking for. Probably two or three times anyway. You don't want to get aggressive and remove a lot of metal, because that will affect how far the bolt is withdrawn. Remove too much metal and the bolt will not retract enough to free the cylinder. I just removed enough to do the job. When I was done, the gun worked fine, and the C&B cylinder still worked fine too.
Who did you buy the cylinder from? If you bought it from Taylors, give them a call, I am sure they will make it right. You will probably have to send the gun to them so they can adjust things. If you bought it from an after market seller like Midway, call Taylors and see what they say.
If your cylinder is the six shot 45 Colt version, it was made under license from Taylors. Keeny Howell does not make a six shot 45 Colt conversion cylinder for the 1858 Remmie. If yours is five shots, Kenny Howell made it. Cal him and see what he says.
Or, if you feel handy you could try what I did.
