I've handled a New Model Army by Pietta that seemed a little difficult to unlatch the ramrod but not allow it to go into the cylinder, half-cock it so the bottom 'dog' exits the notch in the side of the cylinder, and ? to get the spur to exit the back of the cylinder, all the while trying to pull forward on the 'wedge' of the spindle/shaft of the cylinder...all at the same time???
I noticed the same problem with my new 1858 Pietta. The cylinder spindle shaft was difficult to pull out and difficult to re-engage. This seems to have loosened up after firing 100 or so rounds.
I find it best to cock the hammer just enough so that both the hammer itself and the hand are withdrawn into the frame of the gun. Then the cylinder drops out freely and installs freely. This is not half-cock but somewhat less than that I think.
It can be a bit fiddly to keep the loading ram from dropping into one of the cylinder bores during extraction, but I find it helpful to allow it to do so during re-installation as it helps align the cylinder for the spindle. But this is with an empty cylinder where the ram has someplace to go. This might not be true with a loaded cylinder depending on how deep your balls are set.