Perfectly normal trigger operation, Redcoat.

What you're feeling is the sear dragging across the hammer's half-cock notch in double action.

BITD, it was found objectionable by the reviewers in the gun magazines so much so that S&W eliminated the notch after they installed the firing pin safety.

The 1st gens had only the half-cock notch in the event of an unintended hammer drop.

The 2nd gens had both the half-cock notch and the firing pin safety.

By the advent of the 3rd gens, the din from the magazine writers became overwhelming and the half-cock notch was eliminated and the firing pin safety was it.

John