Hi all new here. First I don't have one yet mainly because I wanted some info on the barrel used. I have heard it is made of 4140 steel with a Armornite (melonite) finish inside and out that has been sprayed on and then heated. From what I have also read was that the process for treating steel rifle barrels was to heat the barrels first and then soak in Melonite/Nitride. So my questions are, IF someone knows, what process does S&W use and how durable is the finish?

It is a salt nitride bath... nothing "sprayed on".

And I understand that this process also make the steel harder, slicker and more durable, correct?

Yes, that is correct.