I have personally stood up on my hind legs and hit targets at 200 meters with a powerful handgun.
In fact, that was the original IHMSA (International Handgun Metallic Silhouette Association) shooting game, where you take down five steel rams in two minutes, using iron sights. But it is still only a partial answer to the question of how far a handgun will shoot with any predictable accuracy.
I have also set up a Ransom Rest and fired at targets as far out as 200 yards, producing groups as small as 2 to 3 inches. When Elmer Keith first worked with the pre-war Registered Magnums, he propped up an old door and consistently hit it at more than 600 yards.
I have personally observed such good handgun shooters as Dave Spaulding and Ken Hackatrorn consistently ring a Pepper Popper at 100 yards, using service grade autos with sights designed for the close work of 7 yards or less.
The limitations in the range of handguns are more in the sighting system than in the pure mechanical sense. And most of all, the limitations are in the handgunner and not the handgun. Just learn to shoot and it will all come together.