The lock itself doesn't matter to me. The reason I want an older gun is because the older gun is usually a better gun. A firing pin on the hammer would be best. I have a late model 686 Plus, timing was off on 3 chambers in the cylinder, sent it back to S&W, they replaced the extractor, now it has a hitch on 2 or 3 of the chambers. The gun is functional but shooting D/A with it isn't what it should be. Get an older 6 shot gun if you can find one. I have a 586 that's a real pleasure to shoot. I have a late model 642, has a burr in the forcing cone but still works fine, and a 625 JM, had to send the 625 back to S&W to have the extractor replaced, it also has a dish on the rear end of the bbl like someone took a swipe with a dremel on the left side. They did replace the extractor, didn't address the bbl even tho I pointed it out to them. The gun works for IDPA and it is one of my favorites but it's not what it should be. I prefer their older guns but not because of the lock.