Just one quick pointer: On a S&W or Ruger revolver, you've probably not going to get that "welded to the frame" lockup. That's OK though, as long as it comes back when to center when it wiggles.
But the quick-check is a good one. Helped me spot a tuned S&W M-19 under cover of worn-bluing and light freckling. Best deal I've ever gotten! Millet sights, Hogue grips, a Milt Sparks holster, almost perfect timing and lockup, and it is the only gun that has ever been CLEAN when I got it home.
NRA Master - Highpower Rifle, Across the Course
NRA Expert - Highpower Rifle, Mid-Range Prone