All your gun is, is a Model 19 Combat Magnum in stainless steel. It was, and IS, one of the finest Police "duty weapons" ever created in a revolver. It was the brain child of Border Agent Bill Jordan, whom persuaded Smith and Wesson into the endeavor.
It was, and IS, my all time favorite defense weapon when loaded with 125 grain jacketed hollow points in 357 magnum. I have owned a total of about 8 of these, and have fired thousands of rounds thru two in particular giving shooting demos including aerial targets. This gun in a four inch is a natural pointer, and due to its shape came out of the holster QUICK.
Ask anyone whom knows anything about Bill Jordan. Weak? Yea, Right! ANY revolver in this type of configuration will eventually go out of time if given a steady diet of full house defense ammo, but it will take hundreds of rounds. I once shot two out of time giving demos shooting very lightly loaded 38s. I put new cylinder hands in both and continued shooting them until I wore the cylinder stops out. Refitted them, and sold them. I would give almost anything if I had, had the good sense to keep them all. They are a Police Classic. My preference was the 19 over the stainless 66.
It is a K frame revolver, but unless your a marathon shooter like I was when I was instructing, it will last you a lifetime under normal shooting, even if you shoot a lot.