What handgun cartridge designed by John Browning in 1905, for use in his prototype Colt semi-automatic pistol, is chambered in a third-generation semi-automatic pistol from Smith & Wesson's 4500 series of handguns?
.45 ACP The .45 ACP (Automatic Colt Pistol), or .45 Auto (11.43×23mm) is a handgun cartridge designed by John Browning in 1905, for use in his prototype Colt semi-automatic pistol. After successful military trials it was adopted, along with the Browning .45 Colt handgun, as the .45 M1911 cartridge. The handgun was designated M1911 pistol.
.50 BMG The .50 Browning Machine Gun (.50 BMG, 12.7×99mm NATO and designated as the 50 Browning by the C.I.P.) is a cartridge developed for the Browning .50 caliber machine gun in the late 1910s. Entering service officially in 1921, the round is based on a greatly scaled-up .30-06 cartridge. Under STANAG 4383, it is a standard cartridge for NATO forces as well as many non-NATO countries. The cartridge itself has been made in many variants: multiple generations of regular ball, tracer, armor-piercing (AP), incendiary, and saboted sub-caliber rounds. The rounds intended for machine guns are linked using metallic links.