And The Winner Is... The .30-06 Springfield
Then we come to the .30-06 Springfield, my pick as the greatest rifle cartridge of the 20th century .Before you disagree, take a look at its track record. For starters, the .30-06 was the primary battle cartridge of American military forces from its introduction in 1903 until it was replaced by the 7.62mm NATO in 1954. That’s over half a century of military duty. During that time the United States and its allies won the two greatest wars in the history of modern mankind, and while they would likely have done so had the .30-06 not been around, the cartridge played a key role nevertheless. Long before the old soldier retired from military duty it was enjoying tremendous popularity among hunters and target shooters. Today, the .30-06 is No. 1 in sales among all big-game cartridges with the major ammunition manufacturers, and it is seldom out of the top five most popular chamberings among builders of bolt-action rifles. The grand old cartridge has long been available in all types of rifles: bolt actions, slide actions, single shots, autoloaders, and even a few lever actions. A great abundance of factory loadings are available not only from U.S. manufacturers but from those in other countries as well. Federal alone, as an example, offers almost two-dozen different loadings of the .30-06 Springfield with bullet weights ranging from 125 to 220 grains. Handloaders who load the cartridge have a great variety of brands, styles, and weights of bullets from which to choose, and dozens are suitable for this grand old cartridge. The popularity of the .30-06 is worldwide; it accounts for a big chunk of sales among many foreign manufacturers of sporting ammunition, and any foreign rifle manufacturer who is anybody (and even some who aren’t) offer the .30-06 chambering. The .30-06 got a head start on its competition by being adopted by the US Military, same as the .45-70 Government, .30-40 Krag, .308 Winchester, and .223 Remington. Today, it is a benchmark by which big-game cartridge performance is compared.

So there you have the greatest cartridge of the 20th century along with its 11 runners-up. I’m sure everyone won’t agree with all of my picks, but that was one of the great things about 20th-century America—we could disagree and still be friends.