Legend has it that the “plow handle” grip shape of early pistols was chosen because it would feel natural to the average man back in those days?
Samuel Colt’s Paterson .36 caliber revolver was his first to incorporate the wider at the bottom and narrower at the top profile, but it took later Colt models like the Walker, Dragoon and Navy revolvers to bring the plow handle design to popularity. The heavier recoil of these guns—like the .44 caliber Colt Dragoon—meant the shape of the plow handle grip would allow the revolver to pivot gently in the user’s hand, coincidently bringing the single-action hammer into position for faster re-cocking.
Later, the longer and more vertical “Bisley Grip” improved on the plow-handle style grip. Heavier than a plow handle, the Bisley Grip could handle recoil better and was a solid choice for hotter loads, as well as for shooters with larger hands.
Today, the humble plow handle grip remains a popular choice for single-action revolver aficionados, mostly thanks to its ability to mitigate recoil well.
Like many things when it comes to firearms, the best choice of grip style for a single-action revolver is purely subjective. One may fit your hands better, while another will tame recoil to your liking. The only way to really know which grip is best for you is to experiment with different grip types until you find a winner.