Although I have seen fluted cylinders with a chamber wall blown out that was rare compared to the actual problem. The earliest fluted cylinders were bored straight from front to rear. The thin metal in the area near the cylinder stop notches, due to pressure when firing, would bulge out and cause the stop bolt to be unable to engage the stop notch and index the cylinder properly. When the hammer was clocked the cylinder would over rotate, going past the proper battery position.
Colt remedied this by drilling the cylinder chambers with a taper leaving more supporting metal in the area around the stop notches. In the end Colt determined that the rebated cylinder was a better design and knowing how Colt ran his business it was probably a little less expensive to manufacture the rebated cylinder.