_Monocular Vision._—Seeing with only one eye. When one eye is closed, as some do in taking sight with a gun, it is a case of monocular vision. _Mould._—An implement for moulding bullets. The plural form is generally given to it, as bullet moulds. _Musket._—A form of gun, smooth bored and formerly used for military purposes. When grooves are cut in the interior of the barrel, it is called a rifle. _Nipple._—In a percussion-lock gun, the tube upon which the cap is placed. In the central-fire breech-loader, the tube through the standing breech in which the striker or plunger works. _Nipple Wrench._—An implement used for screwing the nipples into position or out. It is often called a tube-wrench. _Oblique Fire._—Indicates that the plungers of a breech-loader lie and strike the ignition obliquely. _Pan._—A small pan-like outside on the flint-lock, which holds the priming, and in which the latter is ignited by a spark from the flint striking the frizzen. _Patent Breech._—See false breech. _Pepper Box Pistol._—One form of revolver pistol, in which the barrels are made full length from one piece of metal. The rotation of the barrels and the action of the lock to fire the arm was produced by pulling the trigger. _Picker._—A small wire implement hung to the shot-pouch of the hunter in the days of the old flint-lock, and used when occasion required for picking priming into the touch-hole of the gun. _Pipes._—Short tubes attached to a barrel or to a rib attached to the barrel to receive the ramrod and hold it in place. _Pistol._—A small variety of fire-arm, so made as to be easily carried in the pocket or a holster, and readily manipulated and fired with one hand. _Pistol Grip._—A gun stock whose grip inclines to turn down like the handle of a pistol, is said to have a pistol grip. _Play._—A rifle which does not shoot with regularity is said to play its balls. _Plungers._—The pins which are struck by the hammers, in breech-loaders, and which in turn strike and explode the ignition. _Powder Bed._—The chamber, in a muzzle-loader, where the powder lies when the gun is charged. _Priming._—The powder in the pan of a flint-lock gun. _Proof Marks._—Impressions of stamps made in gun barrels to indicate that they have been proved. _Proving._—Firing gun barrels with very heavy charges of powder and balls to ascertain if they are of proper strength. _Ramrod._—A rod with which the tightly fitting portions of the charge are pushed home in loading a muzzle-loader. _Rebounding Lock._—A lock which has the top of the mainspring and crank of the tumbler lengthened to such an extent that when the trigger is pulled the hammer delivers its blow and immediately rebounds to the half-cock. _Rib._—The metallic strip lying between and connecting the barrels of a shot-gun. See lower rib and upper rib.