I've got one of life's 'Happy Coincidences' here - I was reading about Elmer Keiths early experimentation FAILURES maybe three hours before 'J' sent me this link to Forgotten Weapons historic Elmer Keith blown-up SAA Cylinder:
- Kinda says it all eh.
You may get away with one or two thou. oversize ... but as much as four thou.( 0.004 inch) is reasonably likely to be an unacceptable and adventurous risk.