Revolvers can most certainly jam. I’ve had it happen. My Python locked up like a bank vault when a bullet backed out of a cartridge one day. Had to have a gunsmith fix it.
Opened my eyes for sure.
L
It’s never happened to me with my S&W .38. I have had semi-autos jam after the primer cap went off defectively, failing to set off the main charge.
Reloaded cartridge?
I had unburnt Unique powder get under the extractor star of a Smith 686 and lock it up. Also, the ejector rod of a pre-1961 .44 mag backed out and jammed once (they changed to a left hand thread in ‘61)