Improvised firearms (sometimes called zip guns, pipe guns, or slam guns) are firearms manufactured by an entity other than a registered firearms manufacturer or a gunsmith. Improvised firearms are typically constructed by adapting existing materials to the purpose. They range in quality, from crude weapons that are as much a danger to the user as the target, to high-quality arms produced by cottage industries using salvaged and repurposed materials.[1][2][3]
Improvised firearms may be used as tools by criminals and insurgents and are sometimes associated with such groups;[4][5] other uses include self-defense in lawless areas and hunting game in poor rural areas.[6]