Dummy cartridges fulfil many purposes and their construction and appearance varies accordingly. It is this wide variation that makes them so interesting to collectors. Although this site will deal mainly with those made for military purposes, notes have been (or will be) included regarding other dummy cartridges that may be encountered, however, these will not be covered in the same amount of detail.
By far the most common dummy cartridges are those made for military purposes, usually instruction. These are "drill dummies" used to practice the technique of loading (and unloading) weapons). Although made in quantities substantially less than live ammunition they usually survive in service for a considerable period, gradually becoming more and more delapidated with constant use. An important feature of military dummies is that they should be immediately identifiable as such, important bearing in mind the way they will be used in training, usually by inexperienced troops. The problem with that requirement is that every nation seems to have their own ideas on what those markings should be, which makes for a varied collection but makes definition far from simple and sometimes almost impossible. Even when there is a "normal" standard, not only can that standard be subject to constant modification over time but emergencies, such as wartime conditions, can lead to a series of expedient measures that bear little or no resemblence to what has gone before.
This is a grey area in the field of military dummies. Studies made of surviving examples seem to indicate that in the absence of suitable manufactured dummy cartridges, servicemen in the field improvised their own using whatever materials were on hand. Without supporting documentation it is often difficult to ascertain the genuiness of these cartridge, especially as they were often of limited and localised manufacture.
Britain and the Commonwealth nations made a series of Inspection dummies, used by armourers to check the functioning of weapons. These should not be confused with tool dummies, which usually come in sets and are in reality gauges used in the adjustment of, for example, head space.
Dummy cartridges may be made for display or promotional purposes; this particularly applies to what are usually referred to as "board dummies", which were attached to display boards with string. This necessitated a series of parallel holes drilled in the case, the number to an extent dependent on the size and weight of the cartridge, the minimum number usually being four, two near the top, two near the bottom. These holes were drilled fairly close together and positioned so that they are not visible from the front of the display. Most of these board dummies have been cleaned and polished. Some may have been given a protecting coat of clear lacquer so that they do not discolour. Because of their limited use, board dummies can be quite scarce.
In addition there are what are known as "factory dummies". These were assembled out of components from current production and mostly consist of an empty unprimed case (normally with flash holes in the the primer pocket but sometimes without) and bullet. Because these were not primarily intended to be loaded into a gun they omit some of the features (such as bullet securement) found on other dummies, nor, for that matter, do they have any special identifying markings. Despite this some have damage caused by loading and those intended to have Berdan primers can show marks on the anvil made by a firing pin. Factory dummies may be encountered with both military and commercial headstamps.