Some complex improvised firearms are not only well-built, but also use mimicry as camouflage, taking the appearance of other items. Improvised firearms in the form of flashlights, cellular telephones, canes and large bolts, have all been seized by law enforcement officials. Most of these are .22 caliber rimfires, but flashlight guns have been found ranging from small models firing 22 Long Rifle to larger ones chambered for 410 bore shotgun shells.
While most improvised firearms are single-shot, multiple-shot versions are also encountered. The simplest multi-shot zip guns are derringer-like, and consist of a number of single-shot zip guns attached together. The Pepper-box design is also used in home made guns because it is relatively easy to make out of a bundle of pipes or a steel cylinder.
In late 2000, British police encountered a four-shot .22 LR zip gun disguised as a mobile phone, where different keys on the keypad fire different barrels. Because of this discovery, mobile phones are now X-rayed by airport screeners worldwide. Authorities believe they were manufactured in Croatia, and they still turned up in Europe as late as 2004, according to a report by Time magazine.