A carbine is an intermediary gun, shorter than a long rifle, but longer than a pistol. It was originally a format developed for cavalry to have longarms that were easier to use while on horseback. Many carbines were originally just chopped down long arms, but after a while someone got smart and started chambering pistol calibers into them. They found out that the longer barrel helps increase the velocity of the bullet by not only providing a longer barrel for stability, but focusing the pressures generated by the gunpowder. A 9mm bullet in a luger ( 19mm) casing fired out of a 16" barrel can achieve the same velocities of a .357Sig!!!! And, the accuracy cannot be beat! This is a great choice for an intermediate weapon with a range +/-100m that also allows you to carry a lighter round, and in turn more rounds. Also, the risk of over-penetration is far less with a pistol caliber than a rifle caliber, making carbines the perfect choice for weapons on board aircraft or naval ships.