Ch. 8 Firearms

Question 1

acid etching method

Answer 1

a method in which strong acid is applied to a firearm to reveal the serial number

Question 2

black powder

Answer 2

the oldest gunpowder, which was composed of a mixture of potassium nitrate (saltpeter), charcoal, and sulfur

Question 3

bore

Answer 3

the interior of a gun barrel

Question 4

breechblock

Answer 4

the metal block at the back end of a gun barrel

Question 5

broach cutter

Answer 5

a tool that is pushed through the gun barrel to form the rifling

Question 6

caliber

Answer 6

the diameter of the bore of a firearm (other than a shotgun)

- usually expressed in hundredths of an inch (0.38 caliber) or in millimeters (9 mm)

Question 7

cartridge

Answer 7

ammunition enclosed in a cylindrical casing containing an explosive charge and a bullet, which is fired from a rifle or handgun

Question 8

choke

Answer 8

a device placed on the end of a shotgun barrel to change the dispersion of pellets

Question 9

ejector

Answer 9

the mechanism in a semiautomatic weapon that ejects the spend cartridge from the gun after firing

Question 10

external ballistics

Answer 10

a description of the events that occur after the bullet leaves the barrel of the gun but before it strikes its target

Question 11

extractor

Answer 11

the device that extracts the spend cartridge from the gun’s chamber

Question 12

gauge

Answer 12

the unit used to designate size of a shotgun barrel
- the interior diameter of a shotgun barrel is determined by the number of lead balls that fit exactly in the barrel and are equivalent to 1 lb

Question 13

grooves

Answer 13

the cutout section of a rifled barrel

Question 14

internal ballistics

Answer 14

a description of the events that transpire within the firearm

Question 15

lands

Answer 15

the raised section of a rifled barrel

Question 16

Magnaflux method

Answer 16

a method of restoring a gun’s serial number

Question 17

nitrocellulose

Answer 17

a cotton-like material produced when cellulose is treated with sulfuric acid and nitric acid

• aka guncotton
• used in the manufacture of explosives

Question 18

nitroglycerin

Answer 18

an explosive chemical compound obtained by reacting glycerol with nitric acid
- used in the manufacture of gunpowder and dynamite

Question 19

primer

Answer 19

an igniter that is used to initiate the burning of gunpowder

Question 20

rifling

Answer 20

the spiral grooves on the inside surface of a gun barrel that make the bullet spin

Question 21

semiautomatic pistol

Answer 21

a firearm that fires and reloads itself

Question 22

smokeless powder

Answer 22

an explosive charge composed of nitrocellulose or nitrocellulose and nitroglycerin (double-base powders)

Question 23

striations

Answer 23

fine scratches left on bullets

- formed from contract of the bullet with imperfections inside the gun barrel

Question 24

terminal ballistics

Answer 24

a description of what happens when the bullet strikes its target

Question 25

wad

Answer 25

a plastic, cardboard, or fiber disk that is placed between the powder and the shot in a shotgun shell

Question 26

The accuracy of a firearm can be greatly improved by making the barrel ________ (longer/shorter).

Answer 26

longer

Question 27

The spiral grooves in a gun barrel are referred to as ________.

Answer 27

rifling

Question 28

The rifling on the interior of a gun barrel has spiral grooves and ________.

Answer 28

lands

Question 29

The diameter of a gun barrel, as measured from a land on the left to one on the right, is known as the ________ of a weapon.

Answer 29

caliber

Question 30

A broach cutter is used to cut the _________ in the interior of the gun barrel.

Answer 30

grooves

Question 31

The lands and grooves in a gun barrel are ________ (class/individual) characteristics.

Answer 31

individual

Question 32

Besides grooves, the broach cutter produces fine lines called _________.

Answer 32

striations

Question 33

As bullets emerge from the gun barrel, they rotate, a phenomenon that is called _______.

Answer 33

precession

Question 34

The kinetic energy of a bullet ________ (increases/decreases) as the caliber of the weapon increases.

Answer 34

increases

Question 35

The diameter of a shotgun barrel is expressed as a(n) _________.

Answer 35

gauge

Question 36

The higher the shotgun gauge, the _______ (larger/smaller) the diameter of the barrel.

Answer 36

smaller

Question 37

A sawed-off shotgun is one that has a barrel length less than ________ inches.

Answer 37

18

Question 38

In the past, lead was used to make bullets because it has a high ________.

Answer 38

density

Question 39

Lead's low ______ makes it soften at higher velocities.

Answer 39

melting point

Question 40

The element _________ is added to lead to raise its melting point.

Answer 40

antimony (Sb)

Question 41

The jacket of a cartridge is made from ________ or ________.

Answer 41

copper or brass

Question 42

Black powder is a mixture of _________, _________, and ________.

Answer 42

charcoal (C), sulfur (S), and potassium nitrate (KNO3)

Question 43

Smokeless powder is made from the chemicals ________ and ________.

Answer 43

cordite and ballistite

Question 44

Nitroglycerin is desensitized by adding _______, ________, or _______.

Answer 44

10%-30% ethanol, acetone, or dinitroluene

Question 45

The primer of a cartridge holds a(n) _________ explosive mixture.

Answer 45

stable but shock-sensitive

Question 46

The ________ was a crucial invention needed to make a gun that would fire in any weather.

Answer 46

primer

Question 47

Many firing ranges have banned ________ primers because of their potential health risks.

Answer 47

lead

Question 48

In a shotgun shell, the _________ is designed to make an almost gas-tight seal with the barrel.

Answer 48

wad

Question 49

The matching of fired bullets is carried out by using a(n) _________ microscope.

Answer 49

comparison

Question 50

IBIS is an acronym for _________.

Answer 50

Integrated Ballistics Identification System

Question 51

Serial numbers on handguns can be restored by two methods: the ________ method and the _______ method.

Answer 51

magnaflux; acid etching