As of 2015, the most common rounds in the world are .22 long rifle shells; they can be purchased in large quantities at virtually any retailer of ammunition in the United States. Walmart sells bulk packages of .22 long rifle shells in value packs of 550 rounds.
The first rimfire ammunition was a bullet breech cap made in France for the Flobert indoor target rifle in 1845. The .22 long rifle cartridge was developed by American firearms manufacturer J. Stevens Arms & Tool Company in 1887. It was created by matching a forty grain round-nose projectile with the existing .22 long case, which was itself a development on the older .22 short cartridge.
The .22 long rifle round was immediately popular and was adapted for pistols and rifles. A high velocity version of the .22 long rifle shell was developed after the introduction of smokeless powder. This produced a bullet that shot with a flatter trajectory and extended the popularity of the .22 long rifle shell as a small game hunting and target shooting round.
The cheap price, light recoil and relatively low noise continue to make the .22 long rifle round a popular choice for primary firearms training, recreational shooting, small game hunting and pest control. It is estimated that over 2 billion .22 long rifle rounds are manufactured every year.