All Rifle Calibers
The history of modern rifle ammo roots all the way back to the rimfire Flobert BB cap of France in the 1840s. This cartridge in .22 caliber was developed for indoor shooting, and was the cartridge on which all other rimfire rounds were based. Over the course of time, manufacturers adopted rimfire cartridges to be fired from rifles as small as .22 caliber to as large as .58 caliber. Shooters liked these rimfire cartridges right away, as they were faster and easier to reload in rifles than with a muzzle loader. It was also easier to transport and store.
Winchester introduced their .44 Winchester in 1873, which later came to be called the .44-40 – the first rifle cartridge to enjoy commercial success. It wasn't long before other companies started to develop ammunition for their own rifles, and for competitors' rifles as well. The .45 Colt and the .45-70 are two of the most famous rifle cartridges from 1873.
Smokeless powder was introduced less than 20 years later, and the first commercially successful cartridge to use it was the .30-30 Winchester, released in 1895. Just over 10 years later, the immensely popular .30-06 was released and then adopted by the U.S. military, where it served for over 60 years. Cartridge development was a booming business in the late 19th and early 20th centuries, years that saw the introduction of smokeless powder and rimmed cartridges.
Cartridges and cases continued to grow in size until 1921, at which point we reached the pinnacle with the .50 Browning Machine Gun cartridge. This massive cartridge was not introduced for rifles, but began the trend toward smaller cartridges – mostly possible thanks to continuing advancements in powder, materials and bullet design.
The .270 Winchester, introduced in 1925, is a good example of a smaller cartridge. It's a medium bore cartridge that continues to be among the most well-known and often-used rounds for hunting in North America. National militaries around the world also drove the development and advancement of rifle ammunition, especially during the 1940s, when the .30 Carbine and the 7.62x39mm appeared.
The 1950s and 1960s were innovative times for ammunition, particularly for the Winchester company. Among Winchester's releases during these decades were the .22 Winchester Magnum Rimfire, .243, .300 Winchester Magnum, .308, and .458 Winchester Magnum – and they have remained in great demand since.
While the 70s did not see much innovation for rifle ammunition, its most notable cartridge was the 5.45x39mm. The 1980s and 1990s saw bore sizes growing and cartridge power increasing again with the 7mm-08 Remington and .338 Lapua leading the pack of the "bigger, faster, heavier" cartridges of the era.
Since the start of the new millennium, new cartridges have been scarce, and it's especially hard to speak of any real game changers. If there were one great cartridge we should expect to see being produced in another 50 years, it will likely be the .300 AAC Blackout. As the old saying goes: "The more things change, the more they stay the same." Rifle ammo has changed immensely in the past century, but after all is said and done, it still just boils down to brass, powder, primer and bullet.