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bhemry, I do know but haven’t had any experience with them. Do they work well?

I've thought about it several times over the years since learning of their existence, just never bought one myself. Haven't read any complaints about function after installation.

But in case the S&W internal lock is the only thing stopping you from buying a particular gun, or paying hundreds more for one without it, and for less than $50, you can remove the internal lock and plug the hole yourself- seems like a good option to me.