A quick note of correction and history. The actual
projectile part of a modern round of
ammunition is called the 'bullet' (or 'ball', 'slug'). The term
cartridge actually predates the all-inclusive ammunition concept. During the
American Civil War, for example, the
Springfield Rifle (the most widely-used single-shot
muzzle-loader) was loaded using pre-packaged amounts of
powder that came in
wax paper - those were called 'cartridges.' The term has evolved to indicate a complete, ready to fire round.
The .45 ACP was originally designed and intended to be a cavalryman's weapon - this is why it emphasizes throwing large bullets relatively slowly. Accuracy (never the early M1911's strong suit) was not as important when you were shooting at horsemen, as a hit on either would suffice; if you did hit, you wanted the maximum stopping power, which indicated large, slower bullets.