Taurus International Manufacturing Inc "Technically, the new Titanium Tracker models should be considered an extension of the Total Titanium series. They employ the same total-titanium construction in every major part and component—frame, cylinder, yoke, barrel, studs, and pins. They offer the same advanced metallurgical and design features as the fixed-sight snubnose Total Titanium guns. And, like all other Taurus titanium-component models, the Trackers feature the key-activated Taurus Security System hammer lock. What’s different is the added benefit of a new-for-Taurus full-profile, integrally ported, four-inch titanium barrel design plus topstrap frame modifications to accommodate a heavy-duty, precision-adjustable rear sight, which, as I found out during my range testing, resulted in a surprisingly high level of accuracy.
Truly A Trailblazer
All Titanium Tracker models have titanium frames, sideplates, yokes, and barrels that are drop-forged in Taurus’s metallurgical facility outside Sao Paulo, Brazil. The titanium cylinders and titanium internal studs are CNC-machined from extruded titanium barstock. Taurus acknowledges that in spite of the Total Titanium label applied to the entire family of these guns, not every part is actually made of titanium. Instead, the company’s catalogs and promotional flyers note that the Total Titanium concept means “every component that can and should be made of titanium, is made of titanium.”
..."Accordingly, the hammer, trigger, cylinder latch, ejector rod, and some other small parts such as springs and sideplate screws on all of Taurus’ new titanium series revolvers are made from casehardened, high-tensile-strength chrome-moly steel, which is a better material than titanium for those particular parts."
..."unlike stainless steels or even aluminum—titanium is chemically inert and essentially impervious to corrosion. Even the best grade of stainless steel will eventually rust or corrode. Titanium will not—which is why it’s used for desalinization plant piping and for bone-replacement material for permanent implantation within the human body, among other things. "
Above from:
Taurus Tracker - The First-Ever Total Titanium Field Gun - Page One 
