Page "Firearm" Paragraph 59

A related class of firearm to the submachine gun is the " Personal Defense Weapon " or PDW, which is in simplest terms a submachine gun designed to fire rounds similar to rifle cartridges.

A submachine gun is desirable for its compact size and ammunition capacity, however a pistol round lacks the penetrating capability of a rifle round.

Conversely, rifle bullets can pierce light armor and are easier to shoot accurately, but even a carbine such as the Colt M4 is larger and / or longer than a submachine gun, making it harder to maneuver in close quarters.

The solution many firearms manufacturers have presented is a weapon resembling a submachine gun in size and general configuration, but which fires a higher-powered armor-penetrating round ( often specially designed for the weapon ), thus combining the advantages of a carbine and submachine gun.

The FN P90 and Heckler & Koch MP7 are examples.