Editing Handloading (section)

===Shotgun shells===
[[File:Pacific266.jpg|thumb|right|[[Pacific tool company|Pacific]] single stage shotshell reloading press (an inline design), showing the 5 stations standard to shotshell presses.]]
Unlike the presses used for reloading metallic cartridges, the presses used for reloading shotgun shells have become standardized to contain 5 stations, with the exact configuration of these 5 stations arranged either in a circle or in a straight row.  Nonetheless, the operations performed using the industry-standard 5 station shotshell presses when handloading shotshells with birdshot, although slightly different, are very similar as to when reloading metallic cartridges:
*Selecting an appropriate charge bar and powder bushing, or charge bar with shot bushing and powder bushing, or a universal charge bar (if used) for measuring shot and powder, for the shotshell press.
*Verifying that all components are properly selected (hull, primer, powder, wad, and shot). (No substitutions are allowed in components, nor in charge weights of shot and powder.  The only substitution allowed is in the brand of shot and the size of the shot (#8, #9, etc.  Also, no substitutions are allowed in the shot material itself (whether it is lead shot, Hevi-Shot, steel shot, etc.), as the malleability of lead shot is noticeably different than steel.)
*Loading shot and powder in the press, and verifying that the as-dropped weights are per an established, published, loading recipe using a calibrated scale. (Typically, 5 to 10 trials of shot and powder drops, each, are recommended by shotshell press or universal charge bar user manuals.) 
*Adjusting bushings or universal charge bar settings to account for small differences in densities due to lot-to-lot variations in both powder and shot.
*Inspecting each hull. (Examining for cracks or other hull defects, and discarding any visibly imperfect hulls.  Also, turning each hull upside down to remove any foreign object debris before depriming.)
*Removing the fired primer and sizing/resizing the brass outer diameter at the base of the hull (Station 1).
*Inserting a primer in the well of the press, and sizing/resizing the inner diameter of the hull while inserting a new primer (Station 2).
*Verifying primer is fully seated, not raised.  If primer is not fully seated, re-running operation at Station 2 until primer is fully seated.
*Positioning primed hull (at Station 3), pulling handle down, toggling charge bar to drop measured amount of powder, raising handle, inserting wad, dropping handle again to seat wad, toggling charge bar to drop measured amount of shot, raising handle.
*Pre-crimping of shell (Station 4).
*Final crimping of shell (Station 5).
*Inspecting crimping on shell.  If crimp is not fully flat, re-crimping (Station 5).
*Inspecting bottles of shot and powder on the shotshell press, adding more as needed before it runs out.
*Cutting open 4 or 5 shells randomly selected from a large lot of handloaded shells, respectively, and verifying that the as-thrown weights of powder and shot are both within desired tolerances of the published recipe that was followed. (Optional, but recommended.)

The exact details for accomplishing these steps on particular shotshell presses vary depending on the brand of the press, although the presence of 5 stations is standard among all modern presses.

The use of safety glasses or goggles while reloading shotshells can provide valuable protection in the rare event that an accidental detonation takes place during priming operations.

The quantities of both gunpowder and shot are specified by weight when loading shotshells, but almost always measured solely by volume. A powder scale is therefore needed to determine the correct mass thrown by the powder measure, and by the shot measure, as powder loads are specified with a precision of 0.10 [[grain (mass)|grain]] (6.5&nbsp;mg), but are usually thrown with a tolerance of 0.2 to 0.3 grains in most shotshell presses. Similarly, shot payloads in shells are generally held to within a tolerance of plus or minus 3-5 grains.  One grain is 1/7000 of a pound.

Shotshell reloading for specialty purposes, such as for buckshot or slugs, or other specialty rounds, is often practiced but varies significantly from the process steps discussed previously for handloading birdshot shotshells.  The primary difference is that large shot cannot be metered in a charge bar, and so must be manually dropped, a ball at a time, in a specific configuration.  Likewise, the need for specialty wads or extra wads, in order to achieve the desired stackup distance to achieve a full and proper crimp for a fixed shell length, say 2-3/4", causes the steps to differ slightly when handloading such shells.

Modern shotshells are all uniformly sized for Type 209 primers.  However, reloaders should be aware that older shotshells were sometimes primed with a Type 57 or Type 69 primer (now obsolete), meaning that shotgun shell reloading tends to be done only with modern (or recently produced) components.  Being essentially "published recipe" dependent, antique shotshell reloading is not widely practiced, being more of a specialty, or niche, activity.  Of course, when reloading for very old shotguns, such as those with Damascus barrels, special shotshell recipes that limit pressures to less than 4500 psi are still available, and these "recipes" are reloaded by some shotgunning enthusiasts.  Typical shotshell pressures for handloads intended for modern shotguns range from approximately 4700 psi to 10,000 psi.

Brass shotshells are also reloaded, occasionally, but typically these are reloaded using standard rifle/pistol reloading presses with specialty dies, rather than with modern shotshell presses. Rather than plastic wads, traditional felt and paperboard wads are also generally used (both over powder and over shot) when reloading brass shotgun shells.  Reloading brass shotshells is not widely practiced.

Shotguns, in general, operate at much lower pressures than pistols and rifles, typically operating at pressures of 10,000 psi, or less, for 12 gauge shells, whereas rifles and pistols routinely are operated at pressures in excess of 35,000 psi, and sometimes upwards of 50,000 psi. The [[Sporting Arms and Ammunition Manufacturers' Institute|SAAMI]] maximum permitted pressure limit is only 11,500 psi for 12 gauge 2-3/4 inch shells, so the typical operating pressures for many shotgun shells are only slightly below the maximum permitted pressures allowed for safe ammunition.<ref name ="SAAMI_209">{{cite web |author=SAAMI |title=American National Standards Voluntary Industry Performance Standards for Pressure and Velocity of Shotshell Ammunition for the use of Commercial Manufacturers |url=http://www.saami.org/specifications_and_information/publications/download/209.pdf |access-date=1 March 2013 |archive-url=https://web.archive.org/web/20121115015926/http://www.saami.org/specifications_and_information/publications/download/209.pdf |archive-date=15 November 2012 |url-status=dead }}</ref>  Because of this small difference in typical operating vs. maximum industry allowed pressures and the fact that even small changes in components can cause pressure variances in excess of 4,000 psi, the components used in shotshell reloading must not be varied from published recipes, as the margin of safety relative to operating pressures for shotguns is much lower than for pistols and rifles.  This lower operating pressure for shotguns and shells is also the reason why shotgun barrels have noticeably thinner walls than rifle and pistol barrels.