In car engines and model 4-stroke engines the ring is free to turn, and in fact it will, so wear is even all around the bore. In two strokes, the ring is pinned, and it will move to and fro just a little. It does move though, the more so if the ring wears down.
Removing a ring without distorting it takes a bit of practice, and above all, a piston that is located and fixed well. To that end I use a piece of plywood in my vice to grip the connecting rod and push the piston down until it seats against the wood. I then pull the ring slot outward with my thumbnails, and push the ring inward with my index fingers until it JUST slips over the piston. No more!
The torque generated by the index finger pushing action keeps the ring round when the slot is pulled open, and the outward bending is distributed over the whole ring circumference.