DUMMY CARTRIDGE

An inert cartridge which cannot be fired under any circumstances. In America, an inert cartridge for gun functioning is usually black oxidized and may or may not have holes in the side wall of the case. An inert cartridge for display may be natural colored and should have a hole in the primer cup with holes in the side wall of the case optional.

DUPLEX LOAD

1. A cartridge case containing two projectiles with a single powder charge. 2. A cartridge case containing a single projectile with two types of powder.

DUST COVER

1). A cover over the ejection port of a firearm to reduce the possibility of the entrance of foreign matter into the action. 2). The forward part of a pistol frame which protects the recoil spring.

DUST SHOT

Lead shot having a nominal diameter of .040” or smaller.

DROPPED PRIMER

One that is separated completely from the cartridge or shotshell after firing without obvious distortion of the primer pocket and head.

DRY FIRE

The practice of “firing” a firearm without the use of live ammunition.

DUMDUM BULLET

An obsolete term referring to an expanding bullet manufactured at the British Arsenal in Dumdum, India around 1900.

DOUBLE BASE POWDER

A propellant composed of colloided nitrocellulose and nitroglycerin as its base as opposed to single base powder which has colloided nitrocellulose only as its base material. The percentage of nitroglycerin added ranges from a low of 3% to a high of 39%.

DOUBLE PULL TRIGGER (2 STAGE)

A trigger which has two distinctive pull characteristics. The first or take-up stage is usually long and light in pull force; the second stage having a short but distinct increase in the pull force required to discharge the firearm.

DOUBLE SET TRIGGER

An arrangement of two triggers in which the actuation of one trigger presets the second resulting in a light trigger pull of the latter.