Handloading or reloading is the process of loading firearm cartridges or shotgun shells by assembling the individual components (case/hull, primer, powder, and bullet/shot), rather than purchasing completely assembled, factory-loaded ammunition.
Economy, increased accuracy, performance, commercial ammunition shortages, and hobby interests are all common motivations for handloading both cartridges and shotshells. Reloading fired cartridge cases can save the shooter money, or provides the shooter with more, and higher quality, ammunition within a given budget. Reloading may not be cost effective for occasional shooters, as it takes time to recoup the cost of the required equipment, but those who shoot on a regular basis will see benefit as the brass cartridge case or shotgun shell hull (the most expensive components) can be reused many times (with proper maintenance). Besides economy, the ability to customize the performance of ammunition is a common goal. Hunters may desire cartridges with specialized bullets or specific performance as regards bullet and velocity. Target shooters seek the best achievable accuracy, as well as the best shot-to-shot consistency, or precision. Shotgunning enthusiasts can make specialty rounds not available in commercial inventories at any price. Many handloaders also customize their cartridges and shells to their specific firearms, usually in pursuit of accuracy: they can assemble precision ammunition using cartridge cases that have been fire formed in the chamber of a specific firearm.
Handloaders have the flexibility to make reduced-power rounds for hunting rifles, such as handloading to an equivalent of a milder-recoiling round to encourage recoil-averse hunters to become proficient with a full-power one. Rather than purchasing a special purpose rifle, which many novice hunters would outgrow within a few hunting seasons, a single rifle can be used with special handloaded rounds until such time more powerful rounds are desired and become appropriate. This use of specialized handloading techniques often provides significant cost savings, especially when a hunter in a family already has a full-power rifle and a new hunter in the family wishes to learn the sport. This technique also enables hunters to use the same rifle and caliber to hunt a wider variety of game.
Collectors of obsolete firearms who want to shoot those guns often must handload because appropriate cartridges or shotshells are no longer commercially produced. Handloaders can also create cartridges for which no commercial equivalent exists - wildcat cartridges. As with any hobby, the pure enjoyment of the reloading process may be the most important benefit.