After each shooting session, I decap and clean brass. Decapping consists of using a Universal Decapping Die in my single stage press to remove spent primers. The de-primed cases are then cycled through an ultrasonic cleaner to remove powder residue. My choice is a Lyman Ultrasonic Cleaner with a citric-acid based cleaning solution that does not weaken the molecular structure of the brass.
The cleaned brass is rinsed (preferred in distilled water) and dried. I use compressed air to remove most of the rinse water followed by about thirty minutes in a toaster oven set to 140 degrees to complete the drying.
Once cleaned and dried, brass is sorted into 50 round lots and prepped for the next step - inspection and trimming as required.
Prior to reloading, each case must be inspected and measured to determine if it can be safely reloaded. Shell cases are made of brass and brass does change shape with each use. Close inspection can reveal case head separation, case splits, and other potential problems.
Each cartridge has a standard not-to-exceed maximum length. And, each cartridge has a minimum length. In addition, once primer, powder and bullet are added, each cartridge has a maximum Cartridge Over All Length (COAL or OAL). These measurements are listed in the reloading manuals.
An essential tool for every reloaded is a caliper capable of accuracy to .001 inches. You can use old-school vernier calipers or new style digital or dial readout calipers. While the digital readout provides the necessary accuracy, they do require a battery that is not available at the neighborhood convenience store. My preference is for the dial caliper.
In the beginning is the cartridge length. In general, straight-wall handgun cartridges remain fairly consistent in length through multiply loading and firing sessions. It is important that you measure each cartridge as trim as necessary. Again, while straight-wall handgun loads remain constant, it is important that all cartridges are kept to a consistent length as this length will impact the Cartridge Over All Length; also noted as COAL or OAL.
Next is to clean and prepare the primer pocket and chamfer the case mouth using my RCBS Case Prep Center. The primer pocket requires cleaning to ensure new primers will seat to the proper depth which can be altered due to residual carbon buildup after each use. The case prep center has several power driven stations where different types of cleaning heads can be attached. In the five powered stations, I have installed a carbide pocket uniforming tool, a flash-hole uniforming tool, a pocket brush, and inside and outside case mouth chamfering tools.
Depending on the caliber, primer pockets are large, small, or crimped. Large caliber handguns (.44 Magnum, .45 ACP and others) use Large Pistol Primers).
The .45 ACP is notable as depending on "head stamp" or manufacturer, the primer pocket can be either "large" or "small". While not a complete list, Blazer .45 ACP ammo is "small" primer pocket. Other headstamp brass may or may not be "small" pocket. Generally, a quick visual inspection will determine the difference. If in doubt, a 3/16 pin punch will fit into the "large" primer pocket, but not the "small" primer pocket.
The other oddity primers are from military ammo with "crimped" primer pockets. Those are found in .45 ACP, 9 mm, 5.56, .308 and others. From a visual inspection, they generally exhibit a defined ring around the primer pocket. You can remove the crimp with either a press mounted swaging die or with a carbide "pocket uniforming tool".
The chamfering tools provide a slight inside case mouth bevel to ease bullet seating and to remove burrs left after case trimming. The flash-hole uniformed tool provides a consistent sizing in the case flash-hole. This step is only necessary once in the life of a cartridge.
As a final case prep step, brass is cycled through a tumbler such as the Lyman Turbo Pro 1200. About an hour through the tumbling process (I use medium crushed walnut shell media) produces shiny brass with a majority of the case mars and tarnish removed. Adding a couple of used fabric softener sheets cut into strips or squares helps remove media dust.
These steps provide the good beginning to preparing the cases for the final steps to produce reloaded ammo - sizing, flaring, primer seating, powder charging, bullet seating, and crimping; completing your ammo build.