In American English, a pocket pistol is any small, pocket-sized semi-automatic pistol (or less commonly derringers, or small revolvers), suitable for concealed carry in either a coat, jacket or trouser pocket.Pocket pistols were popular in the United States until the 1950s and 1960s, when most states passed laws limiting or prohibiting the carry of concealed weapons. However, the passage of "shall issue" firearms license laws in the mid-1990s, resulted in a resurgence in the popularity of pocket pistol in the United States, creating new markets for small, simple, reliable, concealed carry firearms.
In general use, the term pocket pistol is purely descriptive, but "mouse gun" (used especially for those of the smallest calibers) is often a pejorative. Likewise, pocket pistols, due to their small size, often are lumped in with Saturday night specials, another pejorative term, which are typically inexpensive small caliber handguns.

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