Letter: U

A heavy duty mechanical device into which chambered barrels are secured for testing ammunition.

1. The complete removal of all ammunition from a firearm and it’s magazine 2. Disassembly of a cartridge or shell.

A rear sight on pistols or revolvers having a flat top with a “U” shaped notch used with bead-topped front sight. Named after Ira Paine, 19th Century match and exhibition shooter. Also known as Paine Sight.

A firearm which, for any reason, is no longer fit for firing.

A gun barrel blank formed by hammering a steel bar to increase its diameter at one end for the purpose of providing a shank section.

The moveable lock of some break-open firearms. It normally engages the barrel lug (underlug) and is actuated by the top lever.

The same as a top break mechanism except that the lever that unlocks the firearm, allowing the barrels to pivot and expose the breech, is located below the trigger guard or forms the trigger guard.

The downward projecting lugs at the breech end of a break-open firearm used for locking and barrel positioning in the frame. Also called Lumps.