Firearms

Question 1

What are microscopes used for in firearms?

Answer 1

To analyze the different rifling and grooves left on a bullet.

Question 2

automatic weapons/ fully automatic

Answer 2

continues to fire as long as its trigger is depressed and ammunition is available

Question 3

semiautomatic weapons

Answer 3

fires and reloads itself before firing another shot; a self-loading weapon

Question 4

Functions

Answer 4

blow-back
recoil
gas piston

Question 5

Blow-back

Answer 5

fired cartridge blows back against the breechblock, forcing it to the rear and extracting and ejecting the expended cartridge casing

Question 6

Recoil

Answer 6

the barrel of the weapon and its breechblock recoil a short distance together

Question 7

Gas piston

Answer 7

gas forces piston to the rear; rod connects the piston to the breechblock so that the breechblock is also pushed to the rear

Question 8

Hundguns- Revolver

Answer 8

Cartridges are held in firing chambers in a rotating cylinder

single action- fired by manually cocking the hammer and then pulling the trigger

Double action- fired by a long trigger pull that raises the hammer, indexes a firing chamber under the hammer, and then allows the hammer to drop, firing the cartridge

Question 9

Double action

Answer 9

fired by a long trigger pull that raises the hammer, indexes a firing chamber under the hammer, and then allows the hammer to drop, firing the cartridge

Question 10

Single action

Answer 10

fired by manually cocking the hammer and then pulling the trigger

Question 11

Semiautomatic pistol (aka autoloaders or self-loaders)

Answer 11

1. cartridge is chambered in the pistol; simultaneously the firing mechanism is cocked
2. shooter pulls trigger, firing cartridge
3. some energy produced by the fired cartridge is used to move the slide or breechblock to the rear
4. spring compressed by the rearward travel of the slide or breechblock

Question 12

Lever Action Rifle

Answer 12

Lever below the weapon’s receiver is dropped to move the breechblock to move the breechblock to the rear and cock the firing mechanism

Raising the lever chambers a fresh round

Question 13

Pump action rifle

Answer 13

AKA- slide action

A slide under the barrel is moved to the rear to extract and eject the expended cartridge and cock the firing mechanism; pushing the slides forward chambers a fresh round

Question 14

Bolt action

Answer 14

Expended cartridge is extracted and ejected by drawing the bolt to the rear; moving the bolt forward strips a fresh cartridge from a magazine and inserts it into the chamber

Question 15

IWA Outdoor Classics

Answer 15

world-leading trade fair for hunting, shooting sports, equipment for outdoor activities and for civilian and official security

Question 16

land and groove rifling

Answer 16

raised portions of the rifling are the lands and the recessed portions are the grooves

Question 17

polygonal rifling

Answer 17

hills and valleys

provides a better gas seal in relatively large diameter bores

produced by hammer forging the barrel around a mandrel containing reverse impression of the rifling

Question 18

Gauges

Answer 18

the diameter of a shotgun’s bore. The gauge is calculated by determining how many lead balls of the same diameter as the bore would weigh one pound

Question 19

smokeless powder

Answer 19

propellant composed of nitrocellulose (single-base) or nitrocellulose plus nitroglycerin (double-base powders)

Question 20

black powder

Answer 20

the original gunpowder, composed of charcoal, saltpeter, and sulfur, now used chiefly in antique firearms and in fireworks

Question 21

NIBIN

Answer 21

National integrated ballistic information network

national database of digital images of spent bullets and cartridge cases that were found at crime scenes or test fired from confiscated weapons

Bureau ATF manages the system and provides the equipment to crime labs around the country.

Question 22

ATF Crime Lab

Answer 22

National firearms examiner academy in Beltsville, Maryland

Invetigators learn to match bullets to firearms, restore obscured or removed serial numbers, and to study crime scene reconstruction

Question 23

Applying the scientific method

Answer 23

3 possible outcomes

1. hypothesis is supported by the data indicating it is possible
2. hypothesis is rejected and excluded as a possibility
3. data is inconclusive

Question 24

OSAC

Answer 24

Organization of Scientific Area Committees (OSAC)

Firearms and toolmarks subcommittee