In 1889, John Moses Browning converted a lever-action rifle into an automatic weapon. This became the basis for the M1895 Machine Gun.
In 1910, Archduke Franz Ferdinand was assassinated with a .32-caliber semi-automatic pocket pistol, designed by John Moses Browning.
In 1911, the US Army adopted the service pistol they would use for the next seventy years, the M1911, still the sidearm of choice for many experts, and still parts-compatible with guns made today. It was, of course, designed by John Moses Browning.
In 1919, General John T. Thompson designed the sub-machine gun that bears his name, often called “the gun that made the Twenties roar”.
In response to Prohibition’s invention of organized crime, the Gun Control Act of 1934 severely restricted civilian ownership of automatic weapons, sawed-off shotguns, silencers, and sundry other items that scared the news media.
In 1935, Fabrique Nationale released a collaboration between Dieudonné Saive and the late John Moses Browning, the Browning Hi-Power, featuring Saive’s invention of the high-capacity double-stack magazine, holding 13 rounds of 9mm ammunition.
Everything since then has been materials engineering.
(and anyone who wants to discuss the feasibility of restricting the supply of ammunition and gunpowder is invited to google for the terms “handloading” and “meth lab”)