I have had a problem in the past, with rotating the cylinder on my ROA.

It turned out, it was the pawl spring, that had broken, this is a small spring, that can easily corrode, and snap.

To get to the pawl spring, dismantle the frame from the grip and trigger guard, by removing the grips, full cock the hammer, and insert a pin into the main spring rod, to take the spring pressure, then releasing the hammer. Remove the three screws around the trigger guard, and the two screws by the hammer that go into the frame, then separate the two parts.

On the left hand side of the frame, just above the screw hole, is a smaller hole, in which you should see a spring. This is the pawl spring, remove it, and check is clean, and intact, also remove the plunger behind the spring, I believe this is the pawl, and check its clean, and moves freely. Obviously if the spring is damaged it will need to be replaced.

Reassemble, the cylinder should rotate freely.