For double action, things that you could do yourself are to replace the rebound spring from the standard 18lb spring to a 16, 15, or 14 lb spring. Polishing the rebound slide where on the sides that ride in the frame also helps. Also, check for both hammer and trigger drag.

Beyond that, to smooth and lighten the action, I recommend a competent gunsmith or a trip to S&W's Performance Center.

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