I read one thread on the S&W forums and the poster sounded intelligent and knowledgable.
He had shot loose “endurance” mod S&W’s. Basically he claimed the endurance mods had improved the package, but overall the gun has not changed much since 1908 (or so). And I think he is right.
The general trend of the thread was that if you were firing something like 5000 rounds a year, and shooting heavy bullets (like 300 grain) you should expect the pistol to loosen up.
I have a M629-4, which has the hammer mounted firing pin. This was made just as the endurance mods were kicking in.
I doubt I have fired 5000 rounds total in the thing. Most of the rounds have been 1000 fps 240 LSWC, or 1200 fps 240 LSWC. Until I got the new S&W grips, the pistol was just unpleasant to shoot with full house magnums.
My 629 is still quite tight, and exceptionally accurate. I don’t plan on ever shooting the big bullets through it, and I hope it will last through my lifetime without ever having to send it to the factory.
So for you, with a pre endurance mod pistol, I think you can shoot ten of thousands of 44 Spl equivalent loads (like 240 LSWC 8.5 grains Unique) without any trouble. As for shooting full power magnums, I would shoot them occasionally. 20 rounds, 40 rounds, sighting in for hunting, won’t hurt the pistol. I would never shoot 300 grain stuff as I do believe that is hard on an N frame, and harder still on older N frames.
If you want something to shoot hottest 44 Magnums till you have elbow problems, go buy a Ruger. The Redhawk and the SuperRedhawk are for those want tendinitis in their wrists and elbows. Fun, fun, fun.
http://en.wikipedia.org/wiki/Tendinitis