A submachine gun, or SMG, is an automatic firearm that is smaller than a regular rifle and uses pistol ammunition. This type of weapon is often used in close-quarters combat due to its compact size and high rate of fire. SMGs are typically equipped with a magazine that houses the ammunition and are designed to fire rounds rapidly with a single pull of the trigger. This makes them ideal for situations that require a fast response, as they can be aimed and fired quickly. Additionally, submachine guns can usually be modified to accept a variety of accessories such as optics, suppressors, and stocks. While they are primarily used by militaries and law enforcement agencies, some countries have laws in place that allow civilians to own SMGs. In any case, these weapons should only be handled by trained professionals who have the necessary knowledge and skill to operate them safely.