A mousegun is most often considered a category of small revolver, or semi-automatic handgun intended for concealed carry (CCW)self defense. Typically such small pistols are of .380 ACP (9mm Short) caliber or less, with .32 ACP, .25 ACP, .22 Long Rifle and .22 Short calibers also being common. The term is used to describe a class of small handguns. The term is also sometimes used to refer to rifles firing bullets smaller than .30 caliber, such as the .223/5.56mm.
The popularity of so-called mouseguns has exploded, coinciding with the increasing popularity of concealed carry weapon (CCW) permits, relaxed CCW attitudes by law enforcement and society, and new mousegun weapon design improvements.
In order to create such small pistols, compromises in the list of features wanted on a gun needs to be made, so many mouseguns lack features such as slide stops and external safeties, and few function quite as reliably as the famously reliable, full-size designs such as the Glock 17 service weapons. The small size and mass of the pistol, and low energy of the smaller cartridges, also could make functioning of semi-automatic versions less reliable. Yet even with the short sight radius and low-profile, snag-resistant iron sights, which are required for meeting the needs for a concealed handgun, some of these mouseguns can shoot 2-inch (5 cm) groups at 21 feet, (6.4 meters,) a typical urban combat distance. It's even possible to shoot a one hole group at 8 - 10 yards (7 - 9 m) with a mousegun.
Examples of revolver mouseguns include the North American Arms Mini Revolver, which is a spur trigger design with birdshead grips. The North American Arms Mini Revolver is styled very much like popular pocket revolvers of the 19th Century, but is made entirely of stainless steel.
Smith & Wesson's "J-Frame" series of revolvers are a common choice for mouseguns. They are generally more reliable than their automatic counterparts, and offer an exceptional power-to-weight ratio, especially the lightweight AirLite and Airweight lines. On the other hand, they offer only five shots (auto mouseguns often hold more rounds), and have considerably greater recoil, especially in .357 magnum.
Particularly small and high-quality examples, such as the Seecamp LWS 32 .32 ACP pistol, formerly commanded prices significantly higher than its US$600 retail. During the mid-1990s, demand so far exceeded supply that contracts for guns were sold up to two years before the guns themselves were produced, and the guns themselves were then often resold for as much as $1100 USD upon delivery.
Since roughly 1995, however, there has been considerable erosion in these high mousegun prices, no doubt a result of Kel-Tec starting to produce a 9 mm mousegun, the Kel-Tec P11, then the .32 ACP P-32 (~$230) and the .380 ACP P3AT (~$260) in 1993, all of which were priced at roughly half the price of the Seecamp LWS, while packaged in much the same size. As of Sept, 2013, the Kel-Tec P-3AT with its unloaded weight of 8.3 oz. (235g), is still advertised as "the lightest .380 Auto pistol ever made."
- Video Review Uploaded on Sep 15, 2008 by Nutnfancy: "A Nutnfancy Tactical Clinic shoot." Shooting the Kel-Tec P-3AT .380: Reliable Backup Field testing a tiny new Kel-Tec P-3AT, watch Nutnfancy shooting 2-inch and 3-inch groups at 7 yards. Retrieved Sept 11, 2013
- Video Review Uploaded on Feb 1, 2009 by Nutnfancy: Shooting Ruger LCP .380: "Amazing Accuracy" Field testing a tiny new Ruger LCP .380, watch Nutnfancy shooting 2-inch (one hole)groups at 8 - 10 yards (7 - 9 m). Retrieved Sept 11, 2013
- KeltecWeapons.com The P-3AT .380 "is mainly intended for plainclothes police officers as a secondary weapon, or for concealed carry by licensed citizens." Retrieved Sept 11, 2013