Not sure from original post if you have checked with S&W re the 624 recall for cylinder material strength/heat treatment. Here is an old contact reference that you may wish to try: Kate Fredette (1-800-331-0852 Ext. 218 ).

I called/emailed to get 2 of my 624s checked [other had red "C" on box].

Good luck and happy shooting.

Regards,

Dyson