The cylinder is what lets go first when a revolver blows up.
Before you go over loading your Rugers a bunch remember this
Redhawk cylinder OD 1.782
Super Black hawk cylinder OD 1.729
S&W N frame cylinder 0D 1.710

Some of it is the location of the stop notch. S&W having theirs right over the chamber on 6 shot models. Ruger's Notch is partially offset which gives it a bit more metal there to.

By the way the new Model Vaquero 45 colts have a smaller 1.672 cylinders