Rather than check the B/C gap with the hammer cocked, you should really check it when the gun is a full lockup. Full lockup means that the trigger is held fully to the rear and the hammer is resting fully forward as it would be when the gun is fired. A good revolver checkout can be found in Jim March's Revolver Checkout thread which is stickied at the top of the revolver forum.
Also, your gun is most likely not chrome plated unless it has been refinished at some point. The two standard finishes for the M19 were blue and nickel and I suspect that you're mistaking nickel for chrome. Finally, stay away from full-power .357 Magnum ammo with bullets lighter than 140gr in your revolver. K-Frames such as your M19 have a thin area at the six o'clock position of their forcing cones that's known to crack if the revolver is fired with large amounts of full-power, lightweight magnums (the full-power 125gr loadings are the most well-known offenders). So long as you stick to either .38 Special ammo or Magnums with heavier bullets, your revolver should last long enough for your grandchildren to enjoy it.
Smith, and Wesson, and Me. -H. Callahan
Well waddaya know, one buwwet weft! -E. Fudd
All bad precedents begin as justifiable measures. -J. Caesar