Editing Handloading (section)

== Accuracy considerations ==
Precision and consistency are key to developing accurate ammunition. Various methods are used to ensure that ammunition components are as consistent as possible.  Since the firearm is also a variable in the accuracy equation, careful tuning of the load to a particular firearm can yield significant
accuracy improvements.<ref name=frfrog>{{cite web |url=http://www.frfrogspad.com/miscellg.htm#accuracy |title=Miscellaneous Questions #7}} What affects the accuracy of ammunition?</ref>

===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 />

===Bullets===
Bullets must be well balanced and consistent in weight, shape, and seating depth to ensure that they correctly engage the rifling, exit the barrel at a consistent velocity, and fly straight.  Buying bullets from a high-quality source will help ensure quality, but for ultimate accuracy, some shooters will measure even the best bullets, and reject all but the most consistent.  Measurement of the weight is the easiest, and bullets that are out of round can be detected by rotating the bullet while measuring with a micrometer.  There is even a device available that will detect changes in jacket thickness and internal voids in jacketed rifle bullets, though its high cost makes it prohibitively expensive for all but the most dedicated shooters.<ref name=frfrog />

The transition from the case to the barrel is also very important.  If the bullets have to travel a varying distance from the case to the point where they engage the rifling, then this can result in variations in pressure and velocity.  The bearing surface of the bullet should ideally be seated as close as possible to the rifling.  Since it is the bearing surface that matters here, it is important that the bullets have a consistent bearing surface.<ref name=frfrog />

===Load tuning===
Tuning load to a gun can also yield great increases in accuracy, especially for standard, non-[[accurize]]d rifles. Different rifles, even of the same make and model, will often react to the same ammunition in different ways. The handloader is afforded a wider selection of bullet weights than can readily be found in commercially loaded ammunition, and there are many different powders that can be used for any given cartridge. Trying a range of bullets and a variety of powders will determine what combination of bullet and powder gives the most consistent velocities and accuracies. Careful adjustment of the amount of powder can give the velocity that best fits the natural harmonics of the barrel (see [[accurize]] and [[internal ballistics]]). For ultimate accuracy and performance, the handloader also has the option of using a [[wildcat cartridge]]; wildcats are the result of shaping the cartridge and chamber themselves to a specific end, and the results push the envelope of velocity, energy, and accuracy. Most, but not all, reloads perform best when the powder selected fills 95% or more of the case (by volume).<ref name=frfrog />