The Model 66 is a great gun. Meant to be shot with specials and carried with Magnums. You will experience some issues after a few humdred Magnum loads and/or a thousand or so .38 specials.
The most common issue is "end shake cylinder'. The cylinder will develop some fore and aft movement and the cylinder gap will seemingly close up. The installation of an "end shake bearing" will corect this and likely stop the issue. Cheap fix.
In life, strive to take the high road....It offers a better field of fire.
"Robo is right" Fuzzball
I fired one of those recently. No magnum rounds, but it was a blast. I had never shot a centerfire revolver before and really liked it. Still considering buying it off of the owner but not sure I want to part with the money.
"For every problem there is always a solution that is simple, obvious, and wrong." - Mark Twain