Guys with medium and larger hands have been tucking their little finger under the handle of their single action revolvers since the introduction of Colt’s Navy Model. This isn’t a big problem with early Navy-gripped blackpowder and cartridge revolvers—and their modern clones—owing to their light weight and relatively mild recoil.
The later, heavy frame Blackhawk & Vaquero can be a chore to handle using this two-finger grip; especially with ‘Ruger/Contender’ loads. The previous fix required a Ruger Super Blackhawk, Hunter or Bisley grip frame, fitting it to your frame, refinishing as necessary and then buying a set of grips to match. With Ruger factory grip frames well over a hundred bucks (when you can find them) this can be a fairly expensive proposition. Texas Grips
offers an alternative in their extended grips for Ruger single action revolvers. At 1/2 inch longer than standard grips and with a proportional flare at the butt, it offers a Dragoon sized grip that preserves the plow-handle profile. The owner, Henry Lance offers these grips in a number of attractive hardwoods and laminates, but Mesquite got the nod for my old Vaquero.
More at: Texas Grips ?Extended? Single Action Revolver Grips | The Sixgun Journal