I think I know the answer, but want verification from the S&W gurus here who do know. On almost every S&W revolver model starting in the late 50's, one of the first series changes was to change the ejector and rod threads from right-hand to left-hand thread. Why was this done? Were the right hand threaded rods more prone to loosening and backing out from the guns being fired?

One reason I ask is, I have to re-tighten the ejector rod on my M57 almost every time I open the cylinder after firing it, or at least checking it to make sure it is tight. My M29-2 extractor screw was loose when I bought the gun, and I haven't fired it (nor do I think it's been fired). Both guns have left-hand thread.