It is important to consider an extension to the basic “lock, stock, and barrel” format of firearms prior to the cartridge era. Breech-loading arms ultimately required a new metal component that supported the lock/latch system and provided a central point for attaching all the parts. Although there are many terms used to define this component, the most common term is frame. In repeating arms, the term receiver is more common; the frame contains additional parts to receive cartridges and feed them into the firing chamber.
Latching the breech closed and opening it for access is a basic tenet of breechloader design. Early breechlocks required only the pressure of the shooter’s hand on a lever or other device to keep the breech from flying open during firing. As ammunition power increased, more robust locking and latching methods evolved.