The single shot Thompson Contender pistol shown in chambered in .500 Whisper. It is suitable for short-range hunting of medium-sized game and can be used with open sights due to the relatively large size of the target. But most hunting pistols are chambered in smaller caliber and intended for small game. The size of the instant kill zone on a rabbit or a squirrel is tiny. While the hunter may have excellent vision and can see a gray animal in grayish underbrush, it’s much harder in low light with the eye focused on the front sight. With the point of focus being three to four feet in front of you, could you clearly see a squirrel at 100 feet? It’s hard enough with high-contract black bullsye that doesn’t move, and it’s even harder with a well-camouflaged rodent that doesn’t stay put.
Handguns have surprisingly good inherent mechanical accuracy. The limitations in accuracy are imposed mainly by the unsteady hold and by coarse aiming devices. The unsteadiness is solved by using a bipod or another support, the lack of adequate sight picture by the use of optics. Since we already determined that most of us can see game animals at reasonable handgun ranges, magnified optics are optional. However, both scopes and red dot sights fulfill the first, most important purpose of handgun optics — bringing the reticle and the target into the same focus plane. Once you are able to see clearly, all other fundamentals — smooth trigger press, range estimation, follow-up — can be put to good use. Not much of a point in perfect technique if the sight picture is inaccurate to begin with, as it has to be with focus being required on the front sight at four feet and on the target at a 100.