Unfortunate, but most folks around here who've had to send a gun back to S&W report a positive experience -- certainly not all, but most. My experience with most customer service is the better I treat them, the better they treat me.

Are you handy with revolvers? If so, before you send it consider some of the advice already given in this thread, especially the loosened ejector rod possibility.

If you're comfortable with the internals, consider too a complete tear down and cleaning and oiling, then put 'er back together and see -- might be something simple is out of place (like, say, the hammer block) that's an easy fix.

Ironically, this can be the frustration of tuned, tight tolerance pieces...