Editing Handloading (section)

===Cases===
[[File:Common Empty Rifle Casings.jpg|thumbnail|right|Common Rifle Casings]]
The internal volume of the cartridge case, or case capacity, significantly affects the pressure developed during ignition, which significantly affects the velocity of the bullet.  Cases from different manufacturers can vary in wall thickness, and as cases are repeatedly fired and reloaded the brass flows up to the neck and is trimmed off, increasing capacity as well as weakening the case.  The first step to ensuring consistent case capacity is sorting the cases by headstamp, so each lot of cases is from the same manufacturer and/or year.  A further step would be to then weigh these cases, and sort by case weight.<ref name=frfrog />

The neck of the case is another variable since this determines how tightly the bullet is held in place during ignition.  Inconsistent neck thickness and neck tension will result in variations in pressure during ignition.  These variables can be addressed by annealing and thinning the neck, as well as by careful control of the crimping operation.<ref name=frfrog />