Check out this two-part weapons video to see how to prepare a .223 cases for reloading.
This video shows in chronological order all the steps needed to prepare .223 rifle brass to be reloaded. The cases are tumble cleaned, resized and de-primed, the resizing lubrication is removed, any military primer pocket crimps are removed by swaging, the cases are trimmed to length, the case necks are de-burred and chamfered inside and out, and a new primer is installed into the primer pocket. After this point, the cases are ready for powder, bullet seating and bullet crimping, which are not shown in this video.
Multiple methods are demonstrated for trimming and chamfering, and the advantages of full synthetic motor oil as case lubricant for the resizing process is demonstrated. This case preparation process is essentially the same for almost any rifle brass.