Reloading supplies / Bullets, or handloading is the process of making firearm cartridges and by assembling the individual components (case, primer, propellant, and projectile), rather than purchasing mass-assembled, factory-loaded ammunition.

The term handloading is the more general term, and refers generically to the manual assembly of ammunition. Reloading refers more specifically to handloading using previously fired cases and shells. The terms are often used interchangeably however, as the techniques are largely the same, whether the handloader is using new or recycled components. The differences lie in the initial preparation of cases and shells; new components are generally ready to load, while previously fired components often need additional procedures, such as cleaning, removal of expended primers, or the reshaping and resizing of brass cases.

A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. The term is from Middle French, originating as the diminutive of the word boulle (boullet), which means “small ball”. Bullets are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax. Bullets are made in various shapes and constructions (depending on the intended applications), including specialized functions such as hunting, target shooting, training and combat. Bullets are often tapered, making them more aerodynamic. Bullet sizes are expressed by their weights and diameters (referred to as “calibers”) in both imperial and metric measurement systems. For example: 55 grain .223 caliber bullets are of the same weight and caliber as 3.56 gram 5.56mm caliber bullets. Bullets do not normally contain explosives (see Incendiary ammunition and Exploding bullet), but strike or damage the intended target by transferring kinetic energy upon impact and penetration (see terminal ballistics).