It is very possible that a very small sliver of steel flecked loose from your action (or a piece of bronze bristle broke off of your bronze brush, or a sliver of aluminum from the handle of your bronze brush) and has worked its way down into your ejection system. The action is hard to operate because you are grinding metal on metal. Putting oil on it helps a little, but not much. You can't lubricate your way out of this problem.
Open the cylinder, push in on the ejection rod all of the way, and look underneath the ejector piece (the t daisy-like part that pushes out the rims of the empty shells). Look in bright light, really carefully. You may see the piece of metal under there. If so, then the ejector part can't go all of the way back to its flat sitting position when you let go of the rod, and it is therefore slightly elevated. This makes it push really tight against the cylinder wall when you close the cylinder and try to work the action, making the action really stiff to work. (By the way, if the ejection rod has come unscrewed just a bit, then this could also create the same "binding" problem. If this is the case, then go ahead and tighten it up and see if this solves the problem.)
If you don't see anything under the ejector piece, then go ahead and unscrew the ejector rod all of the way out, remove it, remove the ejector, and clean everything out of the works that you can with dry swabs and air. Reassemble and very lightly oil it, and see if this fixes the problem.
If this doesn't fix it, then don't open up the action or lockwork itself. Take it to a good gunsmith and let him open it up.
Hope this helps.
Mannyrock
