To make things easier to follow, I'll be breaking this up into many parts and discussing each section separately.
In addition, I will not make a claim for a single manufacturer, but rather identify multiple finalists/contestants/candidates.
First, I'll talk about semiautomatic pistols with centerfire calibers. Let me explain why I think some well-known businesses didn't make the cut.
I'm not including the big three American pistolmakers—Colt, Smith & Wesson (S&W), and Sturm, Ruger—despite the fact that this may appear unpatriotic.
(I personally choose the Ruger P97.45 ACP), but they aren't widely used by law enforcement agencies or private citizens outside the United States.
First producing arquebus barrels in 1526, the company's wares were "blooded" in combat 45 years later by the Venetian fleet at the Battle of Lepanto.
The Italian gun manufacturer Fabbrica d'Armi Pietro Beretta and its American arm, Beretta USA, are experts in their field.
M1911.45 ACP autopistol and become a household name in the process, but the company is not nearly as well-known today for either the 1911 or autopistol as it was a century ago.