I do agree with the ignition issues from poor fitting caps etc. I should clarify that I refer to flashover on the front end. There is plenty of evidence of issues relating to caps causing the flashover effect.

I Don't grease the chambers either,black power and its substitutes create enough mess without grease everywhere too. I do wonder if this is used in the US in place of Alox where it seems to be common place to grease every time?

For very small chamfers it's quite possible this is a result of de-burring at the factory as a <0.5mm chamfer could be done as part of the process to clean up the machining on the lower cost revolvers.