The topic has bubbled up again and I have renewed interest in it.
Under what it felt was legal and political pressure, S&W re-engineered its revolvers to include an internal lock. Why they didn't do this with the semi-autos is a mystery to me. Why just pick on revolvers?
I like many didn't buy new revolvers for several years, but finally gave in. I had decided I would just ignore the lock. Store the keys in the box and forget about it. That was until I totally stripped the 629 to send it to Magna Port. The Infernal Lock mechanism is so convoluted and appears so fragile that I've decided to remove and plug the hole. There have been reported incidents of revolvers locking up because of a failure of this device. Not many admittedly but reputable reports by Asoob lead me to believe I be better off without it.
Here'a picture of my gun and then a picture from the SightM1911 forum.


Rather than grind off the part and leave the false impression that it works. I'm opting to remove the parts altogether. There is a gentleman who has started a cottage industry on making plugs to fill these holes. You can't just put a "plug" in the hole but need a way to secure it. He provides a new yoke to replace the existing one, along with the plug. So you reuse the spring. Put the other parts in a baggy and put in the box with the key for the next owner.
These are examples of his Stainless polished and satin plugs for the K, L, & N frames.

Not the greatest of web sites, but that's not his forte.
https://www.originalprecision.com/lock-delete-parts.htmlI ordered it last night and he acknowledged it right away and will drop it in the mail today.
Going on the 5" 629 and if I like it I'll probably put one on each of my competition guns.